BOIL WATER ADVISORIES & HEALTH RISK IN NL
USING QUANTITATIVE MICROBIAL RISK ASSESSMENT TO DETERMINE IF HEALTH RISK WARRANTS BOIL WATER ADVISORIES IN NEWFOUNDLAND AND LABRADOR: TIME FOR A NEW APPROACH
By
PAULA V. DAWE
B.Sc.(Eng), University of Guelph, 1999
A thesis submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE in ENVIRONMENT AND MANAGEMENT
We accept this thesis as conforming to the required standard
...... Dr. Hugh Whiteley, Thesis Supervisor University of Guelph
...... Dr. Matt Dodd, Thesis Coordinator School of Environment and Sustainability
...... Dr. Chris Ling, Director School of Environment and Sustainability
ROYAL ROADS UNIVERSITY
September 2013
© Paula Dawe, 2013 BOIL WATER ADVISORIES & HEALTH RISK IN NL 2
Abstract
The effectiveness of Boil Water Advisories (BWAs) as a public health risk management tool is increasingly being questioned. Newfoundland and Labrador’s zero- risk policy for issuing BWAs on public drinking water systems has resulted in over 210 active BWAs annually, the majority classified as long-term BWAs. BWAs are more likely to occur on small systems, in communities with low economic capacity, and in communities without a certified operator. No relationship was found relating confirmed cases of water-related illness to BWAs.
Quantifiable health risk associated with BWAs was evaluated using Quantitative
Microbial Risk Assessment (QMRA). Data on source water pathogen concentrations and epidemiological data was used to evaluate and calibrate the QMRA Model. The study demonstrated the application of QMRA in determining whether health risk warranted issuing a BWA. Eleven recommendations were made on how the province could adopt
QMRA in establishing an alternative drinking water risk management and advisory framework. BOIL WATER ADVISORIES & HEALTH RISK IN NL 3
Table of Contents
Abstract ...... 2 Table of Contents ...... 3 List of Figures ...... 5 List of Tables ...... 6 List of Abbreviations ...... 7 Acknowledgements ...... 8 Chapter 1: Introduction ...... 9 Research Questions and Objectives ...... 12 Significance and Scope of Research ...... 13 Definition of Important Terms ...... 14 Organization of Thesis ...... 15 Chapter 2: Literature Review ...... 16 Boil Water Advisories...... 16 BWAs in Newfoundland and Labrador...... 20 Waterborne Disease ...... 23 Waterborne disease in Newfoundland and Labrador...... 28 Health Risk and QMRA ...... 32 Pathogens and drinking water sources...... 35 Summary of Results from a Survey of the Literature ...... 37 Chapter 3: Methodology ...... 40 Study Sites ...... 40 Data Collection ...... 43 Statistical Analysis ...... 46 Characteristics of drinking water systems on BWAs...... 46 Length of time on BWAs...... 46 Relationship between BWAs and enteric illness...... 46 QMRA Modelling ...... 47 Using QMRA model to determine source water pathogen levels during outbreaks. 47 QMRA calculated health risk for 12 communities on BWAs...... 48 Possible cases of enteric illness attributable to BWAs...... 50 Health risk and Source water quality of drinking water systems on BWAs determined using QMRA model...... 53 Using QMRA to determine if the health risk warrants a BWA...... 54 Chapter 4: Results ...... 57 Characteristics of Drinking Water Systems on BWAs ...... 57 Length of Time on BWAs...... 57 Health Risk Posed by BWAs ...... 60 QMRA Modeling ...... 60 Source water pathogen levels during outbreaks using QMRA...... 60 QMRA calculated health risk for 12 communities on BWAs...... 63 Estimate of actual cases of enteric illness...... 67 BOIL WATER ADVISORIES & HEALTH RISK IN NL 4
Health risk and source water quality of drinking water systems on BWAs determined using QMRA model...... 67 Using QMRA to determine if the health risk warrants a BWA...... 72 Chapter 5: Discussion ...... 76 Effects of Data Limitations on Results ...... 76 QMRA model structure...... 78 Characteristics of Communities on a BWA ...... 79 BWAs and Health Risk ...... 80 Using Health Risk to Determine if BWAs are Warranted ...... 86 Policy Implications of Results ...... 86 Chapter 6: Conclusions And Recommendations ...... 89 Conclusions ...... 89 Characteristics of communities on BWAs...... 89 Health risk posed by BWAs...... 89 Recommendations ...... 91 Policy recommendations...... 91 Recommendations for future research...... 94 References ...... 96 Appendix A: Public Drinking Water Systems in Newfoundland and Labrador on BWA as of March 31, 2012 ...... 110 Appendix B: Raw source water quality data for microbiologic parameters ...... 124 Appendix C: Epidemiological data on enteric waterborne illness in Newfoundland and Labrador ...... 139 Appendix D: Reference Material from Health Canada’s QMRA Model (version 11_07) ...... 142
BOIL WATER ADVISORIES & HEALTH RISK IN NL 5
List of Figures
Figure 1. Year active BWAs were issued as of March 31, 2013...... 22 Figure 2. Laboratory confirmed cases of enteric illness in Newfoundland and Labrador: 1979-2011...... 30 Figure 3. Location of 12 representative communities on BWAs– Newfoundland...... 41 Figure 4. Location of 12 representative communities on BWAs– Labrador...... 42 Figure 5. Probability distribution of DALY risk for confirmed cases of enteric illness. . 71 Figure 6. Probability distribution of DALY risk for high estimate of actual cases of enteric illness...... 71 Figure 7. Probability distribution of DALY risk for Burgeo BWA issued May 7, 2010. 75 Figure 8. Probability distribution of DALY risk for Mainland BWA issued September 29, 2010...... 75
BOIL WATER ADVISORIES & HEALTH RISK IN NL 6
List of Tables
Table 1. Number and type of BWAs on public drinking water systems in Newfoundland and Labrador ...... 21 Table 2. Public and private drinking water systems and BWAs in Newfoundland and Labrador as of March 31, 2012 ...... 24 Table 3. Summary of values of interest derived from epidemiological and drinking water studies ...... 27 Table 4. Confirmed waterborne disease outbreaks in Newfoundland and Labrador ...... 29 Table 5. Summary of values of interest derived from epidemiological and drinking water studies specific to Newfoundland and Labrador ...... 32 Table 6. Standard reasons for issuing a BWA and 12 representative communities on BWAs with mean tap water E. Coli counts ...... 43 Table 7. Annual BWA and enteric illness data as of March 31 ...... 48 Table 8. QMRA input data for 12 representative communities on BWAs ...... 51 Table 9. QMRA input data for Burgeo and Mainland BWAs ...... 56 Table 10. ANOVA analysis of various characteristics of drinking water systems on BWAs and not on BWAs ...... 58 Table 11. Correlation between length of time on a BWA and various factors ...... 61 Table 12. Correlation between total annual number of BWAs and number of days communities spent on BWAs and number of cases of enteric illness ...... 62 Table 13. Giardia concentrations during outbreaks in Newfoundland and Labrador as determined by the QMRA Model ...... 64 Table 14. QMRA output data for 12 representative communities on BWAs ...... 65 Table 15. High and low estimate of average actual number of cases of enteric illness in Newfoundland and Labrador ...... 68 Table 16. Comparison of calculated cases of enteric illness versus confirmed cases of enteric illness ...... 69 Table 17. QMRA model health risk of communities on BWAs using confirmed cases of enteric illness and high estimate of actual cases ...... 70 Table 18. QMRA Model inputs and outputs for Burgeo and Mainland 2010 BWAs...... 74
BOIL WATER ADVISORIES & HEALTH RISK IN NL 7
List of Abbreviations
ANOVA Analysis of Variance
AWWA American Water Works Association
BC British Columbia
BWA Boil Water Advisory
CFU Colony Forming Units
DALYs Disability Adjusted Life Years
DBP Disinfection By-Product
ENVC NL Department of Environment and Conservation
HAA Haloacetic Acids
LSD Local Service District
MAC Maximum Acceptable Concentration
NL Newfoundland and Labrador
PCR Polymerase Chain Reaction
PDF Probability Distribution Function
QMRA Quantitative Microbial Risk Assessment
THM Trihalomethanes
USEPA United States Environmental Protection Agency
WHO World Health Organization BOIL WATER ADVISORIES & HEALTH RISK IN NL 8
Acknowledgements
Firstly, I would like to thank my long-time boss and mentor at the Newfoundland and Labrador Department of Environment and Conservation, Haseen Khan, who encouraged me to pursue my Master’s degree and supported the work involved in undertaking this thesis. I would also like to thank ADM, Martin Goebel, for all his actions in enabling me to be able to undertake this thesis.
I extend my sincerest thanks to my supervisor, Dr. Hugh Whiteley, for taking on this role and providing me valuable feedback throughout the development of my thesis.
I am grateful to government staff from the Department of Environment and
Conservation, Health Canada, and the Department of Health and Community Services who provided the data, tools and background information I needed in order to complete this thesis.
Lastly, my thanks and admiration go out to the communities and water system operators of Newfoundland and Labrador who work so hard to provide clean and safe drinking water to their residents. People tend to take water coming from the tap for granted, but we don’t.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 9
Chapter 1: Introduction
Boil Water Advisories (BWAs) are public announcements issued by a regulatory agency responsible for drinking water advising the public that they should boil their drinking water prior to consumption (Health Canada, 2009). BWAs are typically issued as a result of confirmed microbiological contamination or the possible risk of microbiological contamination. Most jurisdictions across Canada publish lists of active
BWAs on public (municipal) and semi-public (hotels, campgrounds, trailer parks, restaurants, etc.) drinking water supplies. A BWA may also be termed a Boil Water
Notice or Boil Water Order depending on the jurisdiction (Health Canada, 2009).
The definition of a public drinking water supply differs from jurisdiction to jurisdiction. For example, Nova Scotia and Ontario both have clearly outlined definitions based on the number of connections, population serviced, length of time in the year a population is serviced, and type of facility (Nova Scotia Environment, 2013; Ministry of
Environment, 2012). Newfoundland and Labrador defines a public drinking water system as “a water supply system operated by a community” and a private drinking water system as “a water supply system (surface or groundwater) operated by a private individual or group of individuals” (Department of Environment and Conservation
[ENVC], 2002).
The number of active BWAs in a jurisdiction is frequently used as a measure of drinking water safety by the regulatory agency, the media and the public. On April 7,
2008, the Canadian Medical Association reported that there were 1766 BWAs in place across Canada, not including 93 in First Nations communities (Eggertson, 2008, p. 1261). BOIL WATER ADVISORIES & HEALTH RISK IN NL 10
Newfoundland and Labrador had the third most BWAs at 228, behind Ontario at 679 and
British Columbia at 530 (Eggertson, 2008, p. 1261). The number of BWAs, however, provides only a one-dimensional view of a much larger and more complex issue.
Newfoundland and Labrador has established a bacteriological standard for drinking water with the objective of reducing the risk of enteric illness. This bacteriological standard forms the basis for the issuing of BWAs in Newfoundland and
Labrador. The standard calls for a maximum acceptable concentration (MAC) for E. coli of none detectable per 100 mL; that all water entering the distribution system, after a minimum 20 minute contact time, contain a residual disinfectant concentration of free chlorine of at least 0.30 mg/L; and that a detectable free chlorine residual must be maintained in all areas in the distribution system (ENVC, 2008b). According to recent
Health Canada and World Health Organization (WHO) guidance documents (Health
Canada, 2010, 2011a, 2011b, 2011c, 2011d; World Health Organization [WHO], 2011), these standards no longer reflect best practice. Drinking water quality guidelines are now focused on different types of health based targets including health outcomes, treatment performance and specified technology (WHO, 2011).
More than 10 years on from the deadly E. coli O157:H7 outbreak in Walkerton,
Ontario (O’Connor, 2002), the lessons learned from this and other similar events are already starting to fade, particularly for small water systems (Hrudey, 2011). The merit of issuing BWAs needs to be re-evaluated given their overuse and the perceived lack of risk associated with them. The issuing of a BWA should be a measure of last resort for the protection of public health. Instead, overuse has created a “cry wolf” response with BOIL WATER ADVISORIES & HEALTH RISK IN NL 11 the public resulting in an increasing risk that BWAs may be ignored when they are truly needed (Hrudey, Hrudey, & Pollard, 2006).
BWAs most frequently occur in small drinking water systems; however, factors other than size may play a determining role. Understanding these factors is key to assessing the health risk associated with a BWA, safely reducing the number of BWAs in the province, and ensuring the sustainability of small, rural communities and their drinking water systems. The use of BWAs as a public health risk management tool for drinking water systems is creating a two-tiered system of water supply—larger systems with adequate financial, technical and human resources on one side of the divide, and small systems without on the other. Alternative frameworks for risk management and drinking water advisories need to be investigated that will better reflect actual health risk and address factors affecting small systems.
Quantitative microbial risk assessment (QMRA) can be used to help provide a better understanding of the potential health risk associated with a water system (Health
Canada, 2011a). QMRA uses source water quality data, treatment barrier information and pathogen-specific characteristics to estimate the burden of disease associated with exposure to pathogenic microorganisms in a drinking water source (Health Canada,
2011a). QMRA can be used to estimate a risk outcome for consuming drinking water, assess the adequacy of existing control measures, perform site-specific system evaluations, help facilitate risk communication, and model various worst case scenarios
(Schijven, Teunis, Rutjes, Bouwknegt, & de Roda Husman, 2011). QMRA can also help identify the most economic, effective measures (physical, operational, management) to BOIL WATER ADVISORIES & HEALTH RISK IN NL 12 bring risk within health based targets (Medema & Ashbolt, 2006). Rather than applying
BWAs as a blanket approach to risk management where possible microbial contamination of drinking water is a concern, QMRA can be used to provide guidance on quantifying risk. Policy and decision makers can use QMRA to formulate acceptable levels of health risk, develop risk management plans, and prioritize preventative activities.
Research Questions and Objectives
This study explores the following questions through a mixed methods approach with heavy emphasis on quantitative analysis using statistical methods and QMRA modelling:
• What are the significant characteristics of drinking water systems placed on
BWAs in Newfoundland and Labrador?
• Can QMRA be used to accurately determine the health risk posed by waterborne
pathogens in public drinking water systems in Newfoundland and Labrador that
are on BWAs?
• Can QMRA be used to determine if the health risk posed to a drinking water
system warrants a BWA?
The ultimate goal of this research is to improve drinking water safety in
Newfoundland and Labrador. Within this context, the specific research objectives identified for this thesis were:
a) identify characteristics of significance for communities on BWAs; BOIL WATER ADVISORIES & HEALTH RISK IN NL 13
b) evaluate the health risk posed by drinking water systems on BWAs using
QMRA; and
c) make policy recommendations for the updating of provincial drinking
water standards, integration of QMRA into an improved risk management
and drinking water advisory framework, and improvement of small
drinking water system management.
Significance and Scope of Research
This research is an original contribution to the body of literature on small drinking water systems, BWAs and QMRA. Newfoundland and Labrador is used as a case study to develop a context for the research. In exploring the literature, research on the above topics specific to the province is limited especially when compared to other provinces such as British Columbia, Ontario and Alberta. As the responsibility for drinking water is a provincial mandate, each province has its own regulatory and non-regulatory management framework. In many respects, Newfoundland and Labrador is an outlier when it comes to a unified provincial-territorial approach to drinking water management.
For example, it does not have any legislation specific to drinking water, undertakes drinking water sampling on behalf of communities, and is less focused on enforcement.
While the province may be considered lacking in some areas of drinking water safety, this less-restrictive, more flexible approach has allowed a drinking water management framework to develop that is tailored to the specific needs of the province and that excels in other areas of drinking water safety (e.g., public access to drinking water quality data; innovative solutions such as small-scale drinking water treatment systems in rural, remote BOIL WATER ADVISORIES & HEALTH RISK IN NL 14 communities (ENVC, 2012); water system operator education and training). The framework that has evolved acknowledges the unique conditions experienced in the province and that a one-size fits all approach is not necessarily appropriate for small systems. It also allows for new and innovative approaches to be integrated into that framework.
The majority of the literature on BWAs relates to waterborne disease outbreak conditions. The real, everyday challenge for most drinking water system managers and regulators, however, is the prevalence and persistence of long-term BWAs. This study contributes insights into the characteristics of this non-outbreak type of BWA and how these insights can be used to develop alternative frameworks for risk management and drinking water advisories.
Evaluating health risk using QMRA has never been undertaken for drinking water systems in Newfoundland and Labrador. In most of the literature, QMRA has been used in a straightforward manner – input data is collected and health risk is calculated on a single large size system. The potential uses of QMRA as a tool are only starting to be realized. This study contributes insights on the use of epidemiological data with QMRA, and on the use of QMRA as part of a quantitative risk assessment to determine if BWAs are warranted.
Definition of Important Terms
Drinking water advisories are public health announcements, issued by the responsible authority, advising the public that there is an issue with their drinking water. BOIL WATER ADVISORIES & HEALTH RISK IN NL 15
Drinking water advisories include boil water advisories and non-consumption orders
(Health Canada, 2009).
Safe drinking water is drinking water that does not represent any significant risk to health over a lifetime of consumption (WHO, 2011).
Health risk is the risk associated by exposure to drinking water that is contaminated by chemical, microbiological or radiological contaminants expressed as
Disability Adjusted Life Years (DALYs) or number of infections per population. Health
Canada is recommending a health risk target of 10 -6 DALYs per person per year, or an annual risk of infection of less than 1/10,000 (10 -4) persons (Health Canada, 2011a).
Attack rate is defined as is the ratio of cases of illness that occur relative to the total population exposed (Haas, Rose, & Gerba, 1999).
Small systems are public drinking water systems servicing 1500 people or less
(ENVC, 2013).
Organization of Thesis
This thesis is organized into six different chapters. Chapter 1 is an introduction to the research. Chapter 2 reviews the current literature on BWAs, waterborne disease, health risk and QMRA. In Chapter 3, the research methods are described. Chapter 4 is a compilation of the results of the study, while Chapter 5 offers a discussion of the findings and helps interpret the meaning of the results. Chapter 6 offers conclusions, recommendations and suggestions for further research. BOIL WATER ADVISORIES & HEALTH RISK IN NL 16
Chapter 2: Literature Review
A literature review was conducted to identify the number and types of studies that have been conducted on drinking water advisories, waterborne disease, health risk and
Quantitative Microbial Risk Assessment (QMRA). The research was used to discover gaps and common themes to be found in this body of literature, and to mine for data that could be used in the study. Sources included peer-reviewed articles, dissertations, grey literature, on-line databases, and government databases. Relevant publications were traced through Summon, the Royal Roads University library search engine, various article databases, Google Scholar and internet search engines. Bibliographies of some discovered articles were also reviewed for related articles. A variety of grey literature was identified from government websites including sites for the WHO, European
Commission, United States Environmental Protection Agency (USEPA), Health Canada, and ENVC. The grey literature identified encompassed guidelines, annual reports, studies and guidance material on QMRA. Keywords used include: boil water advisory, quantitative microbial risk assessment, Newfoundland, drinking water advisory, small systems, epidemiology, waterborne disease, and health risk. Only English language literature was included in the review.
Boil Water Advisories
Literature on BWAs tends to focus on three areas: i) the number of active BWAs in a jurisdiction, ii) the effectiveness of BWAs in protecting public health, including the extent of compliance by consumers with the instructions in the advisory for safe water use during a contamination event, and iii) guidance for issuing BWAs. Eggertson (2008) BOIL WATER ADVISORIES & HEALTH RISK IN NL 17 reported 1766 active BWAs in place across Canada and the occurrence of many BWAs that have been in place for over five years. Anywhere from 37 to 90% of the public actually complies with BWAs once issued (Butt, 2010; Harding & Anadu, 2000;
Rundblad, Knapton, & Hunter, 2010). Although endemic disease due to public drinking water systems is difficult to quantify, studies estimated that tap water is accountable for between 14-40% of gastrointestinal illness, and that sporadic cases purportedly represent a greater proportion of waterborne disease than cases related to outbreaks (Resebro, de
Franca Doria, Yip & Hunter, 2005). Most of the studies relating to BWAs were undertaken during waterborne outbreak conditions with limited literature on long-term
BWAs and their characteristics.
According to Hrudey (2004), drinking water advisories are often not effective in protecting people from contaminants because they are issued late or not until after an outbreak is already over. Also, people may be non-compliant with water advisories because they did not learn of the advisory, did not adequately understand the meaning or the intent of the advisory, did not remember or were disbelieving. Other identified challenges with respect to BWAs include risk communication and message fatigue
(Grover, 2011).
A study of drinking water advisories in British Columbia found that the odds of being on an advisory increased as the size of the (residential) water system decreased, as the level of treatment decreased, and depended on the type of supply and governance structure (Edwards, Henderson, Struck & Kosatsky, 2012). Surface water supplies were more likely to be on advisories than groundwater supplies. The length of time on the BOIL WATER ADVISORIES & HEALTH RISK IN NL 18 drinking water advisory was also found to be linked to source type and governance structure. Drinking water advisories do not directly measure population health outcomes, as they do not depend on the incidence of waterborne disease.
Decisions concerning boil water advisories are made at the provincial/territorial or local level and can be issued either as a precaution against or in response to a waterborne disease outbreak (Health Canada, 2009). Each jurisdiction has developed its own set of guidelines on when to issue a BWA using a risk management/risk assessment approach.
Some jurisdictions, such as Newfoundland and Labrador, have a zero-risk tolerance approach (ENVC, 2011b). The issuing of a BWA coveys two distinct messages: i) that residents cannot rely on the safety of their drinking water, and ii) that there has been a failure of the drinking water system (Eggertson, 2008). Implicit in the issuing of a BWA is a quick and effective response to undertake any required remedial measures in order to have the BWA rescinded (Health Canada, 2009). However, the practice of maintaining long-term BWAs is common in a number of provinces in Canada. According to Health
Canada (2009) guidance for issuing and rescinding BWAs, such advisories are not intended to be prolonged indefinitely, but to have some resolution.
Guidance on the issuing of BWAs from Health Canada (2009) has left the decision to issue a BWA, in the absence of E. coli , at the discretion of the responsible authority. Grover (2011) comments that there is not much instruction of whether to issue a BWA or not where there is uncertainty about the presence of risk; for example, does the presence of one positive E. coli sample establish enough risk to justify the need for a
BWA. In BC, some health authority officials prefer to issue a BWA based on any slight BOIL WATER ADVISORIES & HEALTH RISK IN NL 19 trigger, whereas others hesitate to issue a BWA until sufficient evidence is available and only issue as a last resort (Grover, 2011, p.63).
The Fraser Health Authority in BC has provided guidance for issuing and rescinding drinking water notices that involves steps such as: i) consulting with the water supplier to gather information on the nature of the threat and any mitigative actions planed; ii) assessing the risk posed to consumers as low, moderate or high; and iii) undertaking site investigations to verify and collect additional information for risk assessment (Fraser Health Authority, 2007).
A BC Ministry of Health (2008) report discussed the value of using turbidity as a criterion for issuing BWAs. The report stressed the fact that no single reliable criterion exists that can determine whether a BWA should be issued or not and that turbidity levels should not be used for such purposes unless there is empirical evidence to support this for the specific water system in question. The report also recommended a consistent, province-wide approach to issuing BWAs. Wallis et al. (1996) proposed that concentrations of Giardia less than three to five cysts per 100 L should not be justification for issuing a BWA.
Both Grover (2011) and Eggertson (2008) discuss the use of BWAs as an alternative to adequate water treatment. Hrudey et al. (2006) discusses the disadvantages of over reliance on BWAs including: message fatigue, creating unnecessary panic among the public, the potential for the public to lose confidence in their water system, and the public not taking future BWAs seriously. BWAs most frequently occur on small water systems and in some cases are being used as an alternative to implementing technical or BOIL WATER ADVISORIES & HEALTH RISK IN NL 20 operational interventions due to a lack of both financial and human resources at the community level, and to avoid unwanted liability (ENVC, 2010b).
BWAs in Newfoundland and Labrador.
In Newfoundland and Labrador, there are 21 standard reasons for issuing a BWA including detection of E. coli and protozoa, lack of disinfection or a disinfection system, and operation and maintenance issues with the distribution or disinfection system
(Department of Health and Community Services, 2003; ENVC, 2011b). Typically less than 10% of active BWAs in the province can be attributed to confirmed microbiological contamination that poses a quantifiable health risk to the public (ENVC, 2009, p. 29).
The majority of BWAs are issued as a precautionary measure. The level of public compliance by residents of communities in the province placed on BWAs ranges from
74% to 47% depending on the type of water use (Butt, 2010, p.65).
According to ENVC (2013), there were a total of 219 BWAs on public drinking water systems in Newfoundland and Labrador as of March 31, 2013. The number of active BWAs recorded as of March 31 going back to 2001 is indicated in Table 1, along with the number of communities affected, the population affected, and the type of BWA.
The total number of BWAs declined until 2006, and since then has remained constant at just over 210.
In Newfoundland and Labrador, long-term BWAs are defined as BWAs that have been in place for more than five years (ENVC, 2013). As of March 31, 2013, there were
140 long-term BWAs in the province as indicated in Figure 1, with some dating back as far as 1984 (ENVC, 2013). Many of these long-term BWAs are being used as a band-aid BOIL WATER ADVISORIES & HEALTH RISK IN NL 21
Table 1
Number and type of BWAs on public drinking water systems in Newfoundland and Labrador
2001- 2002- 2003- 2004- 2005- 2006- 2007- 2008- 2009- 2010- 2011- 2012- 02 03 04 05 06 07 08 09 10 11 12 13 Number of BWAs 302 267 242 232 222 215 229 211 218 219 211 219 Communities 164 affected 193 181 159 150 145 145 159 145 157 166 159 Population Affected 66,500 49,900 42,600 42,400 39,700 31,100 51,800 33,800 57,200 40,200 52,400 60,700 % of BWA due to residual chlorination problem (Code E) 32.8 33.0 39.6 33.6 32.4 36.3 37.1 35.1 31.7 34.2 32.7 36.1 % of BWA due to no disinfection system (Code A) 32.5 33.0 33.1 34.9 32.9 25.6 22.3 23.7 22.9 19.2 21.8 19.6 % BWAs due to system broken or no chlorine (Code C) 22.2 17.2 9.50 14.2 15.8 10.7 9.60 14.7 13.8 19.2 17.5 16.9 % of BWAs due to operational problem in distribution system (Code D) 0.30 1.9 2.9 2.2 0 9.3 13 11 14 8.2 9.0 10 % of BWAs due to system is turned off by operator (Code B) 5.6 6.7 8.3 8.2 9.5 8.8 8.3 10 9.2 11 9.9 9.6 % of BWAs due to microbiological (Code F) 6.3 6.7 6.6 6.5 5.9 8.8 9.6 4.7 7.8 7.8 8.1 7.3 % of BWAs due to unspecified/other (Codes G-H) 0.30 1.5 0 0.40 3.5 0.50 0.40 0 0.80 0.90 0.99 0.46 Note. Data comes from ENVC (2002), ENVC (2003), ENVC (2004), ENVC (2005a), ENVC (2006), ENVC (2007), ENVC
(2008a), ENVC (2009), ENVC (2010a), ENVC (2011a), ENVC (2012a) and ENVC (2013). BOIL WATER ADVISORIES & HEALTH RISK IN NL 22
40
35
30
25
20
15
Number of BWAs Issued Number of BWAs 10
5
0
4 6 7 0 3 6 9 0 2 3 5 6 8 9 2 989 992 995 998 001 011 198 1985 198 198 1988 1 199 1991 1 199 1994 1 199 1997 1 199 200 2 200 200 2004 200 200 2007 200 200 2010 2 201 2013 Year
Figure 1. Year active BWAs were issued as of March 31, 2013.
Note. Long-term BWAs are BWAs that have been in effect for longer than five years (prior to 2009). BOIL WATER ADVISORIES & HEALTH RISK IN NL 23 substitute for adequate drinking water treatment. Of the BWAs that were lifted in the
2012-13 fiscal year, 93% were also issued in 2012-13. Only 1.3% of BWAs lifted in
2012-13 were long-term BWAs that had been in place for more than five years.
Approximately 80% of the population in Newfoundland and Labrador gets their drinking water from public drinking water systems, with the remaining 20% relying on private supplies as indicated in Table 2 (ENVC, 2012a). Approximately 10% of the total population was on a BWA as of March 31, 2012 (ENVC, 2012a). BWAs are only issued for public drinking water systems. Public drinking water systems are further classified into very large, large, medium, small, and very small systems based on the population serviced. Approximately 87 percent of active BWAs (as of March 31, 2012) were on very small systems with a population of 500 people or less (ENVC, 2012a). Collectively, the number of days very small systems in the province have spent on BWAs exceeds
580,000 days (as of March 31, 2012).
Waterborne Disease
There are numerous microorganisms in water that can cause illness. The main pathogens of concern in drinking water in developed countries like Canada include different types of bacteria, viruses and protozoa (Health Canada, 2010, 2011a, 2011b,
2011c). Health Canada has established a maximum acceptable concentration for E. coli of none detectable per 100 mL, and treatment performance guidelines of 4-log reduction for enteric viruses, and 3-log reduction for Giardia and Cryptosporidium (Health Canada,
2012).
BOIL WATER ADVISORIES & HEALTH RISK IN NL 24
Table 2
Public and private drinking water systems and BWAs in Newfoundland and Labrador as of March 31, 2012
% of Total Total Duration % of Total Population Population on of Active BWA Number Population Population BWA on BWA BWA (days) Public Systems 514 409,000 79.5 211 52,400 10.2 603,951 Very Large (>50,000) 1 82,300 16.0 0 - - - Large (15,001-50,000) 2 40,100 7.80 1 15,100 2.9 145 Medium (1501-15,000) 41 164,600 32.0 1 1610 0.3 696 Small (501-1500) 82 64,700 12.6 15 10,400 2.0 20,987 Very Small ( ≤500) 358 57,200 11.1 183 25,300 4.9 582,123 Unknown 30 - - 11 - - - Private Systems - 105,500 20.5 - - - - Total - 514,500 100 - - - - Note . Data comes from ENVC (2013). BOIL WATER ADVISORIES & HEALTH RISK IN NL 25
All provinces report on notifiable diseases to the Public Health Agency of
Canada. Enteric disease of possible waterborne origin that is reported on includes campylobacteriosis, cryptosporidiosis, giardiasis, and verotoxigenic E. coli (Public
Health Agency of Canada, 2010). When an enteric illness is identified, standard procedure is to carry out a comprehensive investigation whether it is an individual illness or an outbreak. The investigation will help determine the exposure route (e.g., food, drinking water, recreational water exposure), whether travel played a role in infection, or if there was exposure to farm animals (Department of Health and Community Services,
2011a).
In the case of enteric illness, there are often many cases caused by water and food that go unrecognized (Haas et al., 1999). The actual disease burden can be many times that of laboratory confirmed cases reported by public health agencies. As well, the level of endemic illness can be substantially greater than those occurring during outbreaks
(Haas et al., 1999). All diseases caused by enteric pathogens are likely to be underreported because: i) not all infected persons are symptomatic, ii) those who are symptomatic do not always seek medical care, iii) health-care providers do not always include laboratory diagnostics in their evaluation of non-bloody diarrheal diseases, and iv) case reports are not always completed for positive laboratory results or forwarded to public health officials (Centers for Disease Control and Prevention, 2010). One study found that individuals who had lived for 10 or more years at their current address were less likely to report acute gastrointestinal symptoms and had developed a resistance/ tolerance to a number of enteric pathogens (Strauss, King, Ley & Hoey, 2001). This BOIL WATER ADVISORIES & HEALTH RISK IN NL 26 proposed immunity theory could have implications for individuals with no previous exposure to the same drinking water, particularly for the young, elderly and for immunocompromised individuals.
The detection of outbreaks occurs when the proximity of cases in time and space exceeds some level that becomes noticeable (Haas et al., 1999). Outbreaks depend on the number of persons exposed, the dose and duration of exposure, and the intensity of the outcome. A comparison study of Giardia incidents in two towns in Northern Ontario determined that an actual waterborne outbreak of giardiasis is characterized by consistent positive samples, concentrations of cysts two to three orders of magnitude above background, and an obvious increase in the number of cases in the population served
(Wallis, Matson, Jones, & Jamieson, 2001).
Two of the most influential outbreaks to occur in Canada in recent years in terms of public health and drinking water safety policy include the 2000 E. coli O157:H7 outbreak in Walkerton, Ontario (O’Connor, 2002) and to a lesser extent the 2001
Cryptosporidium outbreak in North Battleford, Saskatchewan (Health Canada, 2001).
The result of both outbreaks was a tightening of regulatory requirements for drinking water systems and adoption of the Multi-Barrier Strategic Action Plan for drinking water safety by all Canadian jurisdictions (Council of the Federation [COF], 2013).
While disease surveillance provides a picture of past risk, it may not accurately reflect future risk. A single organism can initiate an infection of waterborne disease and has been suggested as providing an explanation for sporadic cases of infectious disease
(Haas et al., 1999). Table 3 provides a summary of values of interest from various BOIL WATER ADVISORIES & HEALTH RISK IN NL 27 epidemiological and drinking water studies identified as part of the literature review including the percentage of cases of enteric illness attributable to water, the number of actual cases for every laboratory confirmed case of enteric illness, and the percentage of cases of enteric illness that are travel related.
Table 3
Summary of values of interest derived from epidemiological and drinking water studies
Description of value Value Reference % of cryptosporidiosis cases attributable to Mead et al., 1999; Scallan et water 90-92 al., 2011 % of campylobacteriosis cases attributable Haas et al., 1999; Scallan et to water 3-15 al., 2011 % of E. coli cases attributable to water Haas et al., 1999; Grier & 40-75 Schmidt, 2009 % of giardiasis cases attributable to water Haas et al., 1999; Mead et 60-93 al., 1999; Scallan et al., 2011 % of waterborne illness from public water Charrois, 2010 supplies 67 % of waterborne illness from Charrois, 2010 groundwater/private water supplies 33 % of waterborne outbreaks from public Schuster et al., 2005 water supplies 34 % of waterborne outbreaks from Schuster et al., 2005 groundwater/private water supplies 66 % of Canadians with private water supply Moffatt & Struck, 2011 from groundwater 92 % of water-borne disease events occurred Wilson et al., 2009 among small DWS systems (population less than 5000) 75 Number of actual cases of Thomas et al., 2006 campylobacteriosis for every laboratory confirmed case of campylobacteriosis in Canada 23-49 Number of actual cases of verotoxigenic E. Thomas et al., 2006 coli for every laboratory confirmed case of verotoxigenic E. coli in Canada 10-47 Number of actual cases of cryptosporidiosis 6.9 Health Canada, 2001 BOIL WATER ADVISORIES & HEALTH RISK IN NL 28
for every laboratory confirmed case of cryptosporidiosis North Battleford, SK outbreak Attack rate of Cryptosporidium during Health Canada, 2011a outbreaks (%) 26-40 Attack rate of Giardia during outbreaks (%) Health Canada, 2011a; Haas 30-54 et al., 1999 Attack rate of E. coli during outbreaks (%) 23-50 Olsen et al., 2002 Attack rate of Campylobacter during Jakopanec et al., 2008; Haas outbreaks (%) 22-31 et al., 1999 % of Cryptosporidium cases that are travel Scallan et al., 2011 related 9 % of E. coli cases that are travel related 4 Scallan et al., 2011 % of Giardia cases that are travel related 8 Scallan et al., 2011 % of Campylobacter cases that are travel Scallan et al., 2011 related 20
Waterborne disease in Newfoundland and Labrador.
As indicated in Table 4, there have been 10 confirmed waterborne outbreaks of illness in Newfoundland and Labrador since 1983, affecting approximately 1700 individuals (Battcock, 2009). The last outbreak occurred in 2002, two years after the deadly E. coli O157:H7 outbreak in Walkerton, Ontario (O’Connor, 2002). Between
2003 and 2011, epidemiological health surveillance data indicates there have been 787 laboratory confirmed cases of index enteric pathogens in the province (for Giardia ,
Cryptosporidium , verotoxigenic E. coli , and Campylobacter ) of unknown origin, but possibly linked to drinking water (Public Health Agency of Canada, 2010; Department of
Health and Community Services, 2013). Figure 2 indicates the levels of laboratory confirmed enteric illness in Newfoundland and Labrador for giardiasis, cryptosporidiosis, campylobacteriosis and verotoxigenic E. coli (or E. coli 0157:H7 ). BOIL WATER ADVISORIES & HEALTH RISK IN NL 29
Table 4
Confirmed waterborne disease outbreaks in Newfoundland and Labrador
Confirmed Suspected Age of Outbreak Duration cases of cases of Attack water Main Town Population Year Month (months) Source illness illness rate (%) system cause BWA Harbour substandard No record Grace 2520 1983 April - unknown 5 - - - well Botwood 5053 1991 August 10 Giardia 136 1200 23.7 1941 beavers No record BWA issued until treatment Corner for Giardia Brook 22,410 1992 March 4 Giardia 88 500 2.23 1922 beavers installed Robert's No record Arm 1111 1993 August 4 Giardia 14 125 11.3 1961 beavers Bird Cove 349 1993 August 2 Giardia 8 242 69.3 1963 muskrat No record Springdale 3555 1994 July - Giardia 5 - - - beavers No record Giardia BWA issued until WTP Deer Lake 6320 1994 August - 7 - - 1958 animals installed Appleton/ No record Glenwood 1425 1999 July - unknown - 4 - - sewage Giardia BWA issued until WTP Pasadena 4130 2000 April - 13 - - 1972 sewage installed Botwood 4200 2002 May - Giardia 4 - - - animals No record Note . “-” indicates values were not obtained. Data comes from Battcock (2009).
BOIL WATER ADVISORIES & HEALTH RISK IN NL 30
225
200
175
150 Giardiasis 125 Cryptosporidiosis Campylobacteriosis 100 E. Coli
Cases of Illness Cases 75
50
25
0
3 3 79 89 03 05 991 999 001 19 1981 198 1985 1987 19 1 199 1995 1997 1 2 20 20 2007 2009 2011 Year
Figure 2. Laboratory confirmed cases of enteric illness in Newfoundland and Labrador: 1979-2011.
Note . Outbreaks of giardiasis occurred in 1983, 1991-94, 1999, 2000 and 2002. Data from Department of Health and
Community Services (2013) and Public Health Agency of Canada (2006). BOIL WATER ADVISORIES & HEALTH RISK IN NL 31
Giardia lamblia was the pathogen confirmed to have caused eight out of the ten waterborne outbreaks in Newfoundland and Labrador. While some of these outbreaks have been attributed to animal origin (e.g., beaver, muskrat), hunters, trappers and loggers might have been the source of infection (Khan, 2001).
A comparison of waterborne disease outbreaks in Newfoundland and Labrador versus other jurisdictions indicates Giardia as being the main driver of concern over E. coli or Cryptosporidium (Battcock, 2009). This is in large part due to the lack of agricultural activity and sewage inputs directly into freshwater in the province. As a result, the influence of Walkerton (and North Battleford) on drinking water policy development in Newfoundland and Labrador has not been as marked as in other jurisdictions. Newfoundland and Labrador is one of the only provinces in Canada that does not have a specific drinking water act or regulations (COF, 2013).
Cases of enteric waterborne disease are published by the Newfoundland and
Labrador Department of Health and Community Services (2013) and the Public Health
Agency of Canada (2006). A Food/Water/Enteric Illness Questionnaire must be filled out for every case. The epidemiological follow up investigation can be very revealing as was the case in 2011 when it revealed that two cases of giardiasis were in one individual.
This individual had the illness, was treated, tested negative, and then tested positive again two months later. This individual also tested positive for Cryptosporidium and most likely acquired the infections at a work camp in another province (Department of Health and Community Services, 2011b). BOIL WATER ADVISORIES & HEALTH RISK IN NL 32
A summary of values of interest from various epidemiological and drinking water studies specific to Newfoundland and Labrador can be found in Table 5.
Table 5
Summary of values of interest derived from epidemiological and drinking water studies specific to Newfoundland and Labrador
Description of value Value Reference Average attack rate of giardiasis in NL Battcock, 2009 outbreaks (%) 26.6 Public compliance with BWA in NL– Butt, 2010 drinking water (high) (%) 74.4 Public compliance with BWA in NL– baby Butt, 2010 formula (low) (%) 47.0 % of NL population with private drinking ENVC, 2013 water systems in 2011 20.6 % of NL population on BWA as of March ENVC, 2013 31, 2012 10.2 % of water-borne disease events occurred Battcock, 2009 among small DWS systems (population less than 5000) 62.5 Number of actual cases of giardiasis for Battcock, 2009 every laboratory confirmed case of giardiasis in NL outbreaks 5.7-30
Health Risk and QMRA
QMRA as applied to drinking water is a relatively new area of study. Currently, there is a lack of knowledge and understanding of QMRA models and no systematic application of QMRA in Canada (Payment, 2012). There is an identified need to better understand the benefits of risk assessment models for providing a scientific basis for evaluating if systems can meet health targets, ranking risks and measuring health BOIL WATER ADVISORIES & HEALTH RISK IN NL 33 benefits, triggering boil water advisories, estimating the effect of high impact events, making risk management decisions, optimizing infrastructure investment, setting limits for performance monitoring, and developing appropriate corrective actions (Medema &
Ashbolt, 2006; Payment, 2012; Roser et al., 2006).
The theory behind QMRA is discussed in detail in Haas et al. (1999), Petterson,
Signor, Ashbolt, & Roser (2006), Health Canada (2011a; 2011e), Schijven et al. (2011), and United States Environmental Protection Agency (USEPA, 2012b). Medema &
Ashbolt (2006) identify the need for more data and monitoring programs of water supplies targeted towards the provision of information for QMRA, and more experience with the use of QMRA in areas with high numbers of small water supplies to evaluate its applicability.
QMRA has been incorporated into regulatory development in the drinking water sector in both the United Kingdom and the United States (Pintar, 2008). A risk analysis framework incorporating risk assessment, management and communication has been incorporated into guidance documents on drinking water safety at an international level under broad umbrella terms such as “water safety plans”, “source to tap” and “multi- barrier approach” (WHO, 2004). The transition towards a risk based approach recognizes the inherent flaw in the traditional approach of compliance with drinking water quality standards; by the time adverse water quality results are detected and communicated, the public has already been exposed to contaminated drinking water (Hrudey, 2006). The adoption of the QMRA approach by different jurisdictions has been influenced by large BOIL WATER ADVISORIES & HEALTH RISK IN NL 34 outbreaks of waterborne illness, such as the 1993 Cryptosporidium outbreak in
Milwaukee, USA (Pintar, 2008).
QMRA is a marriage of risk assessment methods with epidemiological models that can be used to compare health risk posed to a population and an individual (Haas et al., 1999). Risk can not only be assessed for outbreak situations, but also for endemic disease when there are low levels of pathogenic microorganisms in water (Haas et al.,
1999). Steps involved in QMRA include: i) determine the concentration of pathogens in raw water, ii) calculate the overall treatment log-removal, iii) determine the resulting pathogen concentration in treated water, iv) determine the number of pathogens ingested per day based on drinking water consumption, v) determine the probability of infection with a given dose of pathogens, vi) determine the probability of illness given infection, vii) determine annual number of illnesses in the population, iix) determine annual health impact (Health Canada, 2011e).
Traditionally, QMRA is used to quantify health risk as the total number of illnesses per year (for a population), the probability of illness per year (for an individual or population) and Disability Adjusted Life Years (DALYs) per year (for an individual or population). Monfared (2010) used QMRA to calculate the annual risk of infection from
Cryptosporidium and Giardia associated with Halifax drinking water to be lower than
1.07x10 -6 and 1.03x10 -5 respectively, 95% of the time. This is well below the WHO health based target of 10 -4. Pintar (2008) used QMRA to ascertain the health risk associated with Cryptosporidium in tap water in the Waterloo Region of Ontario to be 1.5 infections in 10 billion persons per year, well below the WHO health based target of 10 -4. BOIL WATER ADVISORIES & HEALTH RISK IN NL 35
Stalker et al. (2012) used Health Canada’s QMRA Model (version 11_07) to assess annualized risk from Giardia and Cryptosporidium at the two City of Calgary water treatment plants. Results indicated that existing treatment barriers achieve Health
Canada’s target of 10 -6 DALYS per person per year under normal operation and historic protozoa occurrence levels. Overall, however, there is limited information available on quantified health risks of Canadian drinking water systems, in particular for small drinking water systems and systems without comprehensive treatment barriers.
Enger, Nelson, Clasen, Rose & Eisenberg (2012) used epidemiological data to calibrate a QMRA model to produce results consistent with an epidemiological study of diarrhoea cases in children under five in the Democratic Republic of Congo, and to examine health risk under different scenarios in which specific parameter values are varied. The calibration process involved simulating a risk model many times using different input parameter values until the simulation results were consistent with the epidemiological study results. This additional calibration step is not currently part of the
Health Canada QMRA Model (Health Canada, 2011e). As few data exist on pathogen concentrations in developing countries, Enger et al. (2012) also used the QMRA model to predict viable pathogen concentrations in untreated water. Haas et al. (1999) briefly mentions the potential use of QMRA models to back-calculate source water pathogen levels given the number of cases of illness.
Pathogens and drinking water sources.
Microbial pathogens have been identified as the number one risk management priority for drinking water (Hrudey, 2011). There is, however, a lack of data available BOIL WATER ADVISORIES & HEALTH RISK IN NL 36 from pathogenic monitoring of source waters, and what data is available is of questionable quality (Payment & Pintar, 2006). Small drinking water systems are particularly vulnerable to microbial water quality failures (Grover, 2011; Hrudey, 2011;
Kot, Castleden, & Gagnon, 2011). Surface water (and particularly untreated surface water) is the most likely water source to contain pathogens and be on a drinking water advisory (Edwards et al., 2012; Uhlmann et al., 2009).
A study of 72 municipal raw water supplies across Canada chosen based on their willingness to take and ship samples, their reliance on surface water, and recommendations from public health authorities, found 21% (approximately 30% for
Newfoundland and Labrador) of raw water samples tested positive for Giardia cysts and
4.5% (approximately 7.0% for Newfoundland and Labrador) of raw water samples tested positive for Cryptosporidium oocysts (Wallis et al., 1996). This study concluded that potentially human-infective Giardia cysts are commonly found in raw surface waters in
Canada, although cyst viability is frequently low, while Cryptosporidium oocysts are less common. In the study, Giardia cysts were most frequently detected in samples from
New Brunswick, Nova Scotia, and Newfoundland, but most of the water samples contained fewer than 2 Giardia cysts per 100 L. The study also found that water samples contained cysts or oocysts at all times of the year but more frequently in late winter-early spring and fall.
Based on Round 1 of the USEPA Long Term 2 Surface Water Treatment Rule, source water monitoring data collected over the period from 2006-2012 from surface water and groundwater under the direct influence of surface water indicated only 14% of BOIL WATER ADVISORIES & HEALTH RISK IN NL 37 samples tested positive for Cryptosporidium and 84% of samples tested positive for E. coli (USEPA, 2012a). The USEPA database contains more than 40,000 records for
Cryptosporidium and more than 50,000 records for E. coli (USEPA, 2012a). All applicable drinking water systems had to submit monthly samples over a period of two years. There has been some surprise by federal regulators in the US that more
Cryptosporidium oocysts have not been found (American Water Works Association
[AWWA], 2012).
Summary of Results from a Survey of the Literature
It has been observed by a number of sources that the regulatory framework for drinking water does not necessarily work for small communities (Grover, 2011; Kot et al., 2011). The over dependency on BWAs in Newfoundland and Labrador and throughout Canada, particularly for small drinking water systems, is diluting the effectiveness of BWAs in cases where they are truly warranted and creating a rural-urban divide in terms of the quality of drinking water available to the public.
Some common themes contained in the literature reviewed include:
• small drinking water systems are more likely to be on BWAs;
• BWAs are being used as an alternative to drinking water treatment;
• the majority of BWAs in Newfoundland and Labrador are long-term
BWAs;
• the actual waterborne disease burden can be many times that of laboratory
confirmed cases reported by public health agencies; BOIL WATER ADVISORIES & HEALTH RISK IN NL 38
• Giardia is the main pathogen of concern for drinking water systems in
Newfoundland and Labrador;
• QMRA provides the needed link between risk assessment methods and
epidemiological models and data for drinking water systems; and,
• microbial pathogens have been identified as the number one risk
management priority for drinking water.
Major gap areas in data and analysis identified from the literature review include:
• most of the studies relating to BWAs were undertaken during waterborne
outbreak conditions with limited literature on long-term BWAs and their
characteristics;
• endemic disease due to public drinking water systems is difficult to
quantify;
• there is room for interpretation in Health Canada guidance on when to
issue a BWA;
• there is an identified need to better understand the benefits of risk
assessment models, such as QMRA, for providing a scientific basis for
drinking water system management decisions;
• more data and monitoring programs of water supplies are needed for the
provision of information for QMRA;
• there is limited information available on quantified health risks of
Canadian drinking water systems, in particular for small drinking water
systems and systems without comprehensive treatment barriers; BOIL WATER ADVISORIES & HEALTH RISK IN NL 39
• the use of epidemiological data to calibrate QMRA models needs to be
further investigated; and,
• the use of QMRA models to back-calculate source water pathogen levels
given the number of cases of illness needs to be further investigated.
The literature review has provided sufficient background in which to frame the objectives and methodology used in this study. The following sections will help confirm that common themes identified in the literature also apply to the work of this study and to try and help fill some of the identified gap areas in our knowledge of BWAs, waterborne disease, small drinking water systems, and QMRA.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 40
Chapter 3: Methodology
This study used a mixed-methods approach as a methodology, with heavy emphasis on quantitative methods. The research questions posed were answered using a combination of different quantitative methods, with gaps in specific supporting information gathered through qualitative interviews with community water system operators. Statistical analysis was used to determine relationships between drinking water systems on BWAs, different system characteristics, length of time spent on BWAs and enteric illness. QMRA modeling of 12 different public drinking water systems representative of different types of BWAs was also undertaken. Actual epidemiological cases of enteric illness were compared with modeled health risk to help determine the accuracy of the Health Canada QMRA Model results and to back-calculate possible levels of source water pathogens during outbreak and endemic conditions. QMRA was then used to determine if health risk warranted the BWA in two of the 12 drinking water systems examined. This methodological approach was selected because of the availability and suitability of datasets and modeling tools to undertake the required analysis. The methodology selected was also capable of producing useful guidance on possible improvements to the current reliance on BWAs in Newfoundland and Labrador.
Study Sites
All public drinking water systems in Newfoundland and Labrador were considered as sites for this study. Only those 211 drinking water systems on a BWA as of March 31, 2012, as found in Appendix A, were included in the statistical evaluation of
BWA characteristics. BOIL WATER ADVISORIES & HEALTH RISK IN NL 41
A stratified random sample of 12 public water supplies on active BWAs was selected for modeling health risk using available data. The population of 211 BWAs was divided into different strata based on the 21 standard reason codes for issuing a BWA. A random sample or drinking water system was then taken from each stratum. However, not all types of BWA reason codes could be represented as not all types of BWAs were issued as of March 31, 2012. Locations of these 12 sites can be found in Figure 3 and
Figure 4 with information on the type of BWA listed in Table 6.
Figure 3. Location of 12 representative communities on BWAs– Newfoundland. BOIL WATER ADVISORIES & HEALTH RISK IN NL 42
Figure 4. Location of 12 representative communities on BWAs– Labrador. BOIL WATER ADVISORIES & HEALTH RISK IN NL 43
Table 6
Standard reasons for issuing a BWA and 12 representative communities on BWAs with mean tap water E. Coli counts
Standard Mean tap deviation BWA E. Coli E. Coli Town code BWA reason Region (#/100mL) (#/100mL) Water supply has no Churchill Falls A disinfection system W 2.3 2.5 Chlorination system is turned off by the operator, due to taste or other aesthetic B1 considerations Chlorination system is turned off by operator, due to perceived B2 health risks Chlorination system is turned off by operator, due to lack of funds to Piccadilly Head B3 operate W 9.5 11.0 Disinfection system is off due to maintenance Conne River C1 or mechanical failure C 0 0 Disinfection system is off due to lack of chlorine or other Campbellton C2 disinfectant. C 8.0 7.1 Water distribution system is undergoing Bay de Verde D1 maintenance or repairs E 1.0 1.0 A cross connection is discovered in the D2 distribution system Inadequately treated water was introduced into the system due to fireflows, flushing operations, interconnections, minor power outage or Cartwright D3 other pressure loss L 3.5 3.8 Burgeo E1 Water entering the W 0 0 BOIL WATER ADVISORIES & HEALTH RISK IN NL 44
distribution system or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. No free chlorine residual detected in the water distribution Bird Cove E2 system W 12.5 10.7 Insufficient residual disinfectant in water system primarily disinfected by means E3 other than chlorination Total coliform detected AND repeat Little Bay samples can not be (Mine Pond) F2T taken as required C 2.0 1.0 Escherichia coli (E. coli ) detected AND repeat samples can not F2E be taken as required Total coliforms detected and Trepassey confirmed in repeat (Miller's Pond) F3 sample E 1.0 1.0 Escherichia coli (E. coli ) detected in an initial sample(s) is considered extensive and the water system has other known Miles Cove F4 problems C 5.7 5.7 Escherichia coli (E. coli ) detected and confirmed in repeat Mainland F5 sample W 22.1 25.5 F6 Viruses detected F7 Protozoa detected Water supply system integrity compromised G due to disaster Waterborne disease outbreak in the H community BOIL WATER ADVISORIES & HEALTH RISK IN NL 45
Data Collection
Data from existing databases was used in the study including the historical BWA database, tap water bacteriological database, ambient surface water bacteriological database, municipal source water microbiological databases, public water supply database, drinking water quality database, operator certification database, the regional economic capacity index database, and disease surveillance databases. Data was collected from the existing databases on drinking water systems that were both on and not on BWAs.
Source water quality data for microbiological parameters was collected from several sources including (i) the provincial ambient water bacteriological database, (ii) municipal source water microbiological databases, (iii) published scientific research, and
(iv) special field sampling undertaken by the province. Raw source water quality data for microbiological parameters can be found in Appendix B for a limited number of communities in the province. Available data on index pathogens combined with assumptions regarding the relationship of index pathogens to pathogens of interest was used to estimate pathogen counts (Petterson et al., 2006). The largest pathogen dataset was for tap water E. coli , and this was used as the index pathogen. Pathogens of interest include Giardia , Cryptosporidium and Campylobacter .
Due to the lack of source water microbiological data necessary for QMRA, epidemiological data on likely waterborne pathogens was also gathered for giardiasis, cryptosporidiosis, campylobacteriosis and verotoxigenic Escherichia coli . BOIL WATER ADVISORIES & HEALTH RISK IN NL 46
Epidemiological data on enteric waterborne illness of interest in Newfoundland and
Labrador can be found in Appendix C.
Statistical Analysis
Statistical relationships between drinking water systems on BWAs and system characteristics were determined using MINITAB 14 statistical software.
Characteristics of drinking water systems on BWAs.
A one-way analysis of variance (ANOVA) was used to test the equality of population means of drinking water systems that are on and not on BWAs for various responses. The classification factor had two levels: drinking water systems not on BWAs and drinking water systems on BWAs. The means were not equal when the p-value was less than .01 ( α < .01).
Length of time on BWAs.
Pearson’s correlation coefficient was used to examine the degree of linear relationship between different factors and the length of time a public drinking water system was on a BWA. The correlation coefficient assumed a value between -1 and +1.
If one variable tended to increase as the other decreases, the correlation coefficient was negative. Conversely, if the two variables tended to increase together the correlation coefficient was positive. A p-value of less than .01 ( α < .01) for an individual hypothesis test indicated the correlation was not zero.
Relationship between BWAs and enteric illness. BOIL WATER ADVISORIES & HEALTH RISK IN NL 47
An analysis was performed to determine if there was any correlation between annual confirmed cases of enteric illness (giardiasis, cryptosporidiosis, campylobacteriosis and verotoxigenic E. coli ) and the annual number of BWAs (as of
March 31), annual population affected by BWAs (as of March 31), the percentage of
BWA issued for microbiological exceedances (as of March 31), and the cumulative number of days communities in the province spent on BWAs (as of March 31). This data is summarized in Table 7. A p-value of less than .01 (α < .01) was used to determine the significance of the correlation.
QMRA Modelling
Health Canada’s QMRA Model (version 11_07) was used to quantify the probable risk of illness based on source water pathogens and treatment barriers.
Quantitative, statistically evaluated databases of source water microbiology were needed in order to undertake QMRA. Health Canada recommends a minimum of two years of monthly data. In the absence of adequate datasets, an indirect estimate methodology was used to produce datasets for QMRA modeling as discussed in a previous section.
Using QMRA model to determine source water pathogen levels during
outbreaks.
Four of the giardiasis outbreaks that occurred in Newfoundland and Labrador had information on confirmed and suspected cases of illness. Using information on the outbreaks from Table 4 and assuming no treatment barriers, raw water pathogen concentrations were input into the QMRA Model until the total number of illnesses per year in the population approximately equalled the suspected cases of illness in each BOIL WATER ADVISORIES & HEALTH RISK IN NL 48
Table 7
Annual BWA and enteric illness data as of March 31
Cumulative days communities in Number Population NL spent on of affected Year BWA BWAs by BWA Giardiasis Cryptosporidiosis Campylobacteriosis E. Coli 2000 a 51,765 322 83,100 64 1 74 3 2001 a 73,693 302 66,500 45 2 87 5 2002 81,434 267 49,900 35 0 45 9 2003 86,601 242 42,600 29 1 56 4 2004 86,390 232 42,400 29 0 57 2 2005 92,006 222 39,700 22 - 86 5 2006 98,969 215 31,100 35 2 43 0 2007 100,096 229 51,800 23 1 48 10 2008 109,746 211 33,800 45 2 33 4 2009 122,635 218 57,200 24 2 32 4 2010 124,444 219 40,200 35 1 39 0 2011 115,015 211 52,400 43 3 61 6 Average (1979- 2011 non- outbreak) - - - 40.2 1.4 80.5 5.4 Note. “-” indicates values were not obtained. aBWA reporting not considered reliable in 2000 and 2001. BOIL WATER ADVISORIES & HEALTH RISK IN NL 49 giardiasis outbreak. The back-calculated pathogen concentrations were taken to represent actual outbreak concentrations.
QMRA calculated health risk for 12 communities on BWAs.
E. coli counts from the tap water quality bacteriological database were used in the absence of any pathogenic source water quality data. The tap water quality bacteriological database contained thousands of records going back to 2001. E. coli samples were collected at least once a month on public drinking water systems in the province by government staff. Samples were analysed at the Public Health Laboratory and regional testing sites located in hospital laboratories across the province through a quantitative membrane filtration method using a differential medium (Department of
Health and Community Services, 2003). Only positive E. coli counts from the 12 representative communities were extracted from the database in order to provide mean and standard deviations for input in the QMRA Model, as these were considered to be more representative of actual source water quality.
In the absence of site-specific microbiological source water quality data, the
QMRA Model provided typical source water pathogen counts based on the quality of the source water, from pristine to heavily impacted (see Appendix D). These values were approximations based on available sets of pathogen data from several Canadian source waters (Health Canada, 2011e). Linear relationships were developed for
Cryptosporidium , Giardia and Campylobacter in Equations 1-3 based on the typical source water pathogen counts for various source water qualities using E. coli as an BOIL WATER ADVISORIES & HEALTH RISK IN NL 50 independent variable or index pathogen, where all pathogens were measured in counts per 100 L (Health Canada, 2011e):
Giardia = 0.0005 ( E. coli ) + 0.119 , (1)
Cryptosporidium = 0.0001 ( E. coli ) + 0.0238 , (2)
Campylobacter = 0.1 ( E. coli ) + 23.8 . (3)
For pathogens without a site-specific dataset, standard deviation was assumed to equal calculated mean values as recommended by the QMRA Model User Guide (Health
Canada, 2011e). Table 8 summarizes input data for the 12 representative communities on
BWAs that was gathered from various databases or calculated and used in the QMRA
Model. The QMRA Model User Guide recommended using 1.0 L/d as a default value to represent daily water consumption per person in Canada (Health Canada, 2011e). No treatment barriers were assumed as all 12 communities were on BWAs.
The WHO (2011) provided recommendations on minimum levels of water quantity required for health purposes: 2.0 L/p/d for consumption of drinking water and
7.5 L/p/d for hydration and incorporation into food. As part of a sensitivity analysis, a water consumption value of 5.0 L/d was also used in the QMRA Model.
Possible cases of enteric illness attributable to BWAs.
The average number of cases of enteric illness was averaged over the available period of record going back to 1979 in the case of giardiasis, 1989 for campylobacteriosis, 1991 for verotoxigenic E. coli , and 2000 for cryptosporidiosis, excluding years during which outbreaks occurred (see Table 7). The average number of confirmed cases was taken to represent the endemic rate of illness in the province. The BOIL WATER ADVISORIES & HEALTH RISK IN NL 51
Table 8
QMRA input data for 12 representative communities on BWAs
Churchill Piccadilly Conne Bay de Community Falls Head River Campbellton Verde Cartwright Burgeo Bird Cove Little Bay Trepassey Miles Cove Mainland Population (2011 census) 634 139 920 520 398 516 1464 182 108 570 137 341 Daily consumption (L/d) 1 1 1 1 1 1 1 1 1 1 1 1 Mean Cryptosporidium (# per 100 L) 0.25 0.97 0.020 0.82 0.12 0.37 0.020 1.28 0.22 0.12 0.59 2.24 Standard deviation Cryptosporidium (# per 100 L) 0.25 0.97 0.020 0.82 0.12 0.37 0.020 1.28 0.22 0.12 0.59 2.24 Cryptosporidium fraction infectious 1 1 1 1 1 1 1 1 1 1 1 1 Mean Giardia (# per 100 L) 1.3 4.9 0.10 4.1 0.60 1.9 0.10 6.4 1.1 0.6 3.0 11.2 Standard deviation Giardia (# per 100 L) 1.3 4.9 0.10 4.1 0.60 1.9 0.10 6.4 1.1 0.6 3.0 11.2 Giardia fraction infectious 1 1 1 1 1 1 1 1 1 1 1 1 Mean Campylobacter (# per 100 L) 253 973 23.8 823 123 373 23.8 1277 223 123 590 2236 Standard deviation Campylobacter (# per 100 L) 253 973 23.8 823 123 373 23.8 1277 223 123 590 2236 Campylobacter fraction infectious 1 1 1 1 1 1 1 1 1 1 1 1 Mean E. Coli (# per 100 L) 2300 9500 0 8000 1000 3500 0 12533 2000 1000 5337 22125 Standard deviation E. Coli (# per 100 L) 2452 11032 0 7071 1000 3780 0 10750 1000 1000 5386 25548 E. Coli fraction infectious 1 1 1 1 1 1 1 1 1 1 1 1 BOIL WATER ADVISORIES & HEALTH RISK IN NL 52
Coagulation and filtration N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Primary disinfection contact time (min) 0 0 0 0 0 0 0 0 0 0 0 0 Disinfection concentration (mg/L) 0 0 0 0 0 0 0 0 0 0 0 0 Temperature ( oC) 1 1 1 1 1 1 1 1 1 1 1 1 pH 6.82 7.79 5.42 6.64 5.72 5.52 5.02 7.77 7.23 6.22 6.84 8.22 Primary disinfection UV (mJ/cm 2) 0 0 0 0 0 0 0 0 0 0 0 0 Note . N/A = Not applicable; UV = ultra-violet. BOIL WATER ADVISORIES & HEALTH RISK IN NL 53 average number of confirmed cases was then corrected based on information in Table 3 and Table 5 in order to achieve more realistic estimates of actual cases due to local waterborne illness from public drinking water systems. High and low estimates of actual cases were made. Corrections were made for actual versus confirmed cases of illness, travel related cases of illness, cases of illness attributable to food, and cases of illness attributable to private supplies. QMRA modeling was also undertaken for comparison purposes to derive values of total number of illnesses per year, assuming no treatment barriers, based on the average population (2002-2011) on a BWA, the average population on a BWA with no disinfection (2002-2011), and the estimated population in non-compliance with BWAs on drinking water systems with no disinfection taken from
Table 5.
Health risk and Source water quality of drinking water systems on BWAs
determined using QMRA model.
The QMRA model was used to back-calculate source water pathogen concentrations during outbreaks using known suspected cases of illness. The same method was applied using the average number of non-outbreak, laboratory confirmed cases, and the high estimate of actual cases of enteric illness, as determined in a previous section, to determine possible endemic levels of source water pathogens. The latter rate of illness (high estimate of actual cases) was assumed to more closely represent the endemic or sporadic rate of illness associated with public drinking water supplies that are on BWAs. The health risk for each pathogen of interest was compared to the Health
Canada guideline of 10 -6 DALYs per person per year. In this scenario, all towns on BOIL WATER ADVISORIES & HEALTH RISK IN NL 54
BWAs were considered as one large town without any water treatment. The average population on a BWA from 2002-2011 of 48,900 was used for the population of this theoretical town.
Using QMRA to determine if the health risk warrants a BWA.
Of the 12 representative communities on a BWA, two were looked at in more detail to determine if QMRA could be used to establish if the health risk exceeded the
Health Canada guideline of 10 -6 DALYs per person per year for each pathogen of interest, and therefore warranted a BWA. The BWAs in Burgeo and Mainland were selected as these were the only two BWAs with sufficient information to undertake the analysis. The Burgeo BWAs was issued because water entering the distribution system, after a minimum 20 minute contact time, did not have a free chlorine residual of at least
0.30 mg/L. The Mainland BWA was issued because E. coli was detected at 4000
CFU/100 L in the tap water. Additional information was gathered on these two systems for input into the QMRA model including free chlorine residual, pH, water temperature, length of pipe to the first user, diameter of pipe to the first user, and contact time.
Tap water E. coli results were used to determine initial source water concentrations through a series of equations. Using contact time and free chlorine residual, the CT factor was determined from Equation 4 (ENVC, 2005b):
CT factor = residual disinfectant concentration (mg/L) x contact time (min) (4)
Log inactivation of E. coli using free chlorine was then calculated using Equation 5 from the QMRA model (Health Canada, 2011e):
.0 3124 Log Inactivati on = .3 8962 CT . (5) BOIL WATER ADVISORIES & HEALTH RISK IN NL 55
The initial concentration of viable microorganisms (N O) was then calculated knowing the concentration of surviving microorganisms (N T) and Equation 6 (ENVC, 2005b):
NO = ln(Log Inactivati on ) × NT . (6)
The resulting calculated value for source water concentration of E. coli was used to determine levels for Giardia and Campylobacter using Equations 1 and 3 as discussed in a previous section. Cryptosporidium concentrations were set to 0, due to its infrequent detection in the province and the lack of significant numbers of confirmed cases of cryptosporidiosis.
Input values as listed in Table 9 were then entered into Health Canada’s QMRA
Model in order to determine the quantifiable health risk associated with these BWAs.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 56
Table 9
QMRA input data for Burgeo and Mainland BWAs
Community Burgeo Mainland Population (2011 census or at time of outbreak) 1464 341 Daily consumption (L/d) 1 1 Mean Cryptosporidium (# per 100 L) 0 0 Standard deviation Cryptosporidium (# per 100 L) 0 0 Cryptosporidium fraction infectious 1 1 Mean Giardia (# per 100 L) 0.10 2.12 Standard deviation Giardia (# per 100 L) 0.10 2.12 Giardia fraction infectious 1 1 Mean Campylobacter (# per 100 L) 23.8 423 Standard deviation Campylobacter (# per 100 L) 23.8 423 Campylobacter fraction infectious 1 1 Mean E. Coli (# per 100 L) 0 4000 Standard deviation E. Coli (# per 100 L) 0 4000 E. Coli fraction infectious 1 1 Coagulation and filtration N/A N/A Length of pipe to first user (m) 122 400 Diameter of pipe (mm) 450 200 Storage volume (m 3) 1825 0 Average flow (m 3/d) 2193 115.6 Primary disinfection average contact time (min) 372 156 Disinfection concentration (mg/L) 0.10 0.080 Temperature ( oC) 11.1 10.8 pH 5.33 8.14 Primary disinfection UV (mJ/cm 2) N/A N/A Note. UV = ultra-violet.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 57
Chapter 4: Results
Characteristics of Drinking Water Systems on BWAs
The ANOVA analysis had two levels: drinking water systems not on BWAs (N =
305) and drinking water systems on BWAs (N = 207). Forty-six different responses were examined. Several of the responses did not have numerical data and so the categories within the responses were given numerical codes of 0 to 4 (see Table 10). Data for many of the chemical source water quality responses was determined to be highly censored due to less than detect values. Seven of the non-censored responses examined had significantly different means for systems on BWAs compared to systems not on BWAs.
BWAs were significantly more likely to occur in communities that are Local Service
Districts (LSD) (one of four governance structures used for communities in the province– city, municipality, LSD, unincorporated community), that have lower community economic capacity index scores, that have lower trihalomethanes (THMs) and haloacetic acids (HAA) levels, that do not have a disinfection system, that do not have a certified drinking water system operator, and that have smaller populations. Details of these results can be found in Table 10.
Length of Time on BWAs
A sample size of 206 records was used to determine which factors correlated with the length of time a drinking water system had been on a BWA. Length of time was measured in number of days from the date the BWA was issued to March 31, 2012. Five of the factors investigated displayed a significant negative correlation at α < .01 with the
BOIL WATER ADVISORIES & HEALTH RISK IN NL 58
Table 10
ANOVA analysis of various characteristics of drinking water systems on BWAs and not on BWAs
Not on BWA On BWA Responses N Mean N Mean p-value Community Economic Capacity Index 305 47.8 207 31.9 .000* Governance structure- UNC (0), LSD (1), MUN (2) 305 1.74 207 1.46 .000* THMs-none (0), minor (1), moderate (2), major (3) 305 0.957 207 0.406 .000* HAAs-none (0), minor (1), moderate (2), major (3), very major (4) 305 1.19 207 0.44 .000* Disinfection- No (0), Yes (1) 305 0.902 207 0.807 .002* Cadmium 298 0.000150 206 0.000112 .002 Nickel 298 0.00155 206 0.00132 .002 Certified operator- No (0), Yes (1) 305 0.403 207 0.1014 .003* Alkalinity 298 43.9 206 58.1 .008 Population serviced 302 2020 200 266 .009* Treatment- No (0), Yes (1) 305 0.295 207 0.208 .027 Manganese 298 0.0329 206 0.0555 .034 Magnesium 298 3.08 206 3.92 .038 Chromium 298 0.0010 206 0.000884 .070 Copper 298 0.00559 206 0.00409 .116 Bromide 298 0.0274 206 0.0194 .127 Lead 298 0.000626 206 0.00102 .133 pH 298 6.88 206 6.99 .166 Source type- GW (0), SW (1) 305 0.538 204 0.588 .174 Antimony 298 0.000143 206 0.000125 .198 Conductivity 298 166 206 188 .214 DOC 298 4.30 206 4.65 .228 Fluoride 298 0.0624 206 0.0717 .243 Hardness 298 49.1 206 56.2 .246 Arsenic 298 0.00118 206 0.00139 .277 Mercury 298 0.000055 206 0.000050 .307 Sulphate 298 9.73 206 7.05 .314 TDS 298 109 206 120 .324 Region- E (0), C (1), W (2), L (3) 305 0.987 207 1.07 .333 Colour 298 32.4 206 35.5 .340 Ammonia 298 0.0256 206 0.0222 .365 Total Phosphorous 298 0.0155 206 0.0167 .396 Uranium 295 0.000339 206 0.000257 .396 Calcium 298 14.4 206 15.9 .402 Sodium 298 14.2 206 15.9 .434 Potassium 298 0.717 206 0.803 .500 BOIL WATER ADVISORIES & HEALTH RISK IN NL 59
Kjeldahl Nitrogen 298 0.198 206 0.189 .508 Zinc 298 0.0066 206 0.0072 .575 Selenium 298 0.00036 206 0.000384 .608 Barium 298 0.0277 206 0.0309 .637 Turbidity 298 0.88 206 0.967 .654 Nitrate-Nitrite 298 0.121 206 0.134 .667 Iron 298 0.147 206 0.155 .784 Boron 298 0.0187 206 0.0198 .796 Chloride 298 19.6 206 19.4 .932 Aluminium 298 0.099 206 0.0989 .987 Note . Responses highlighted in grey have a censored dataset. Numerical levels for individual responses with non-numerical datasets are indicated. UNC = unincorporated community; LSD = local service district; MUN = municipality; GW = groundwater; SW
= surface water; E = eastern region; C = central region; W = western region; L =
Labrador region; DOC = dissolved organic carbon; TSS = total suspended solids.
*Significant at α < .01.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 60
length of time a drinking water system had been on a BWA as indicated in Table 11.
The length of the BWA was significantly shorter based on the type of BWA (BWAs issued for reason codes A, B and C are longer than for reason codes D, E and F), the season it was issued in (BWAs issued in summer and fall last longer than those issued in the winter and spring), and whether or not the community had a disinfection system, certified operator, or permit to operate the drinking water system (the BWA was of shorter duration if the community had a disinfection system, certified operator or a permit to operate the drinking water system).
Health Risk Posed by BWAs
A correlation analysis was performed to try and detect any link between BWAs and different types of enteric illness. The number of cases of giardiasis, cryptosporidiosis, campylobacteriosis and verotoxigenic E. coli did not show any correlation with the total number of active BWAs as of March 31 of a given year, the population affected by
BWAs as of March 31 of a given year, the percentage of BWA issued for microbiological exceedances, or with the cumulative number of days communities in the province spent on BWAs as of March 31 of a given year at α < .01 as indicated in Table 12.
QMRA Modeling
Source water pathogen levels during outbreaks using QMRA.
The QMRA Model (version 11_07) was used to determine the likely concentration of Giardia in the source water during four of the outbreaks of giardiasis experienced in
BOIL WATER ADVISORIES & HEALTH RISK IN NL 61
Table 11
Correlation between length of time on a BWA and various factors
Pearson correlation Factor coefficient p-value Comment BWA codes from A-H. Length of time on a BWA is significantly correlated with the type of BWA. The length of BWAs for codes A, B and C are significantly longer BWA reason code -.319 .000* than for codes D, E and F. The length of BWAs is significantly correlated with the season the BWA was issued. The length of BWAs is longer for BWAs issued in fall and summer than Season -.367 .000* winter and spring. The length of BWAs is significantly correlated to whether a community has a certified operator or not. Towns without Certified operator -.313 .000* certified operators have longer BWAs. The length of a BWA is significantly correlated to whether a community has a permit to operate or not. Towns without Permit to operate -.386 .000* permits to operate have longer BWAs. The length of a BWA is significantly correlated to whether a system has a disinfection system or not. Systems without Disinfection -.304 .000* disinfection systems have longer BWAs. Serviced population -.130 .068 No correlation Colour .122 .082 No correlation Economic capacity -.114 .103 No correlation DOC .113 .105 No correlation Region -.096 .171 No correlation Water supply protected -.095 .172 No correlation Governance structure .077 .271 No correlation Turbidity -.052 .457 No correlation Iron .045 .518 No correlation TDS -.043 .541 No correlation Conductivity -.042 .554 No correlation pH -.029 .684 No correlation Hardness .014 .840 No correlation Supply type -.004 .951 No correlation *Significant at α < .01. BOIL WATER ADVISORIES & HEALTH RISK IN NL 62
Table 12
Correlation between number of cases of enteric illness and various factors relating to BWAs
% of BWAs due to microbiological Cumulative days exceedance spent on BWA Number of BWAs Population on BWA
Pearson Pearson Pearson Pearson Correlation Correlation Correlation Correlation Coefficient p-value Coefficient p-value Coefficient p-value Coefficient p-value Giardiasis .179 .598 .254 .479 -.225 .533 -.320 .367 Cryptosporidiosis .012 .975 .661 .052 -.785 .012 .011 .977 Campylobacteriosis -.317 .342 -.464 .177 .069 .850 -.048 .895 E. Coli .186 .585 -.307 .388 .476 .165 .621 .055 *Significant at α < .01. BOIL WATER ADVISORIES & HEALTH RISK IN NL 63
the province. Reliable source water pathogen sampling was not undertaken at the time of
the outbreaks, and what data does exist is from outdated analysis methods. Outbreak
concentrations of Giardia as determined using QMRA ranged from 3.4 to 106 cycts/100
L as indicated in Table 13. The annual individual DALY risk was also calculated for each outbreak and ranged from 0.00004 to 0.0012 DALYs, above the Health Canada guideline of 10 -6 DALYs.
QMRA calculated health risk for 12 communities on BWAs.
QMRA modeling results for the 12 representative communities on BWAs are
summarized in Table 14. Except where E. coli input values were 0 CFUs/100 L, the
Health Canada risk level guideline of 10 -6 was exceeded for all pathogens in all communities. These communities were modeled assuming no treatment barriers were in place. These results are noteworthy given the lack of correlation between BWAs and cases of waterborne disease in aggregate.
Results from the sensitivity analysis using a water consumption of 5 L/d can also be found in Table 14. The number of illnesses from Cryptosporidium and Giardia increased approximately 400%. The number of illnesses from E. coli increased from 19-
292%, however, the percent increase was smaller the higher the concentration of E. coli in the drinking water. The number of illnesses from Campylobacter increased up to
219% for concentrations less than 600 per 100 L, an decreased by up to 72% for concentrations greater than 600 per 100 L.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 64 Table 13
Giardia concentrations during outbreaks in Newfoundland and Labrador as determined by the QMRA Model
QMRA model Theoretical Total # of Total # Probability Suspected Giardia illnesses per DALY's per of illness Annual Outbreak Duration cases of (cycts/100 year year per year DALY risk Town Population Year (months) illness L) (population) (population) (individual) (individual) Botwood 5053 1991 10 1200 36 1200 2.04 0.238 0.0004 Corner Brook 22410 1992 4 500 3.4 504 0.857 0.022 0.00004 Robert's Arm 1111 1993 4 125 17 125 0.212 0.112 0.00019 Bird Cove 349 1993 2 242 106 242 0.411 0.692 0.0012 BOIL WATER ADVISORIES & HEALTH RISK IN NL 65
Table 14
QMRA output data for 12 representative communities on BWAs
Churchill Piccadilly Conne Bay de Bird Little Miles Community Falls Head River Campbellton Verde Cartwright Burgeo Cove Bay Trepassey Cove Mainland Population (2011 census) 634 139 920 520 398 516 1464 182 108 570 137 341 Total # of illnesses per year (population)- 7.2 6.1 0.8 19.4 2.2 8.7 1.3 10.6 1.1 3.1 3.7 34.8 Cryptosporidium (36.3) (30.7) (4.19) (97.1) (10.9) (43.5) (6.67) (53.0) (5.41) (15.6) (18.4) (174) Total # of illnesses per year (population)- 14.2 11.7 1.6 36.6 4.1 16.8 2.5 20.0 2.0 5.9 7.1 65.5 Giardia (71.1) (58.3) (7.91) (183) (20.5) (84.1) (12.6) (99.5) (10.2) (29.4) (35.2) (325) Total # of illnesses per year (population)- 21799 6854 6897 25018 9676 20427 10975 9192 3523 13858 6160 16624 Campylobacter (32200) (4770) (22000) (20000) (18100) (25800) (34900) (4930) (5400) (25900) (6190) (4500) Total # of illnesses per year (population)- E. 3236 2042 0 7184 976 3716 0 3395 516 1398 1383 8065 Coli (10800) (4200) (0) (16600) (3830) (11100) (0) (6230) (1860) (5490) (3660) (9660) Total # DALY's per year (population)- Cryptosporidium 0.01228 0.01045 0.00143 0.03304 0.00370 0.01479 0.00227 0.01805 0.00184 0.00530 0.00626 0.05916 Total # DALY's per year (population)- Giardia 0.0241 0.0199 0.0027 0.0623 0.0070 0.0286 0.0043 0.0340 0.0035 0.0100 0.0120 0.1114 Total # DALY's per year (population)- Campylobacter 100.3 31.5 31.7 115.1 44.5 94.0 50.5 42.3 16.2 63.7 28.3 76.5 Total # DALY's per year (population)- E. Coli 79.4 50.1 0 176.3 24.0 91.2 0 83.3 12.7 34.3 33.9 197.9 BOIL WATER ADVISORIES & HEALTH RISK IN NL 66
Probability of illness per year (individual)- Cryptosporidium 0.0114 0.0442 0.0009 0.0374 0.0055 0.0169 0.0009 0.0583 0.0100 0.0055 0.0269 0.1020 Probability of illness per year (individual)- Giardia 0.0223 0.0842 0.0017 0.0704 0.0103 0.0326 0.0017 0.1099 0.0189 0.0103 0.0515 0.1921 Probability of illness per year (individual)- Campylobacter 34.4 49.3 7.5 48.1 24.3 39.6 7.5 50.5 32.6 24.3 45.0 48.8 Probability of illness per year (individual)- E. Coli 5.10 14.69 0 13.82 2.45 7.20 0 18.65 4.78 2.45 10.09 23.65 Annual DALY risk (individual)- Cryptosporidium 1.94E-05 7.51E-05 1.55E-06 6.35E-05 9.30E-06 2.87E-05 1.55E-06 9.92E-05 1.70E-05 9.30E-06 4.57E-05 1.74E-04 Annual DALY risk (individual)- Giardia 0.000038 0.000143 0.000003 0.000120 0.000018 0.000056 0.000003 0.000187 0.000032 0.000018 0.000088 0.000327 Annual DALY risk (individual)- Campylobacter 0.158 0.227 0.034 0.221 0.112 0.182 0.034 0.232 0.150 0.112 0.207 0.224 Annual DALY risk (individual)- E. Coli 0.125 0.361 0 0.339 0.060 0.177 0 0.458 0.117 0.060 0.248 0.580 Note . Values in brackets are for a water consumption of 5 L/d.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 67
Estimate of actual cases of enteric illness.
Confirmed cases of enteric illness in the province were corrected based on various factors gathered from multiple sources to provide an estimate of actual local waterborne cases of illness from public drinking water systems. Preference was given to information from Newfoundland and Labrador, Canada, the United States, then other jurisdictions.
Preference was also given to information that represented endemic illness rather than outbreaks, if available. The results in Table 15 provide both a high and low estimate based on values taken from the literature as summarized in Table 3 and Table 5. A comparison of laboratory confirmed cases, the high estimate of actual cases, and QMRA calculated cases of enteric illness using various correction factors (corrected for percent of population on BWA without disinfection, and percent in non-compliance with BWA) is provided in Table 16. Compared to the high estimate of actual cases, the QMRA model results, even with corrections to the population exposed given endemic conditions, are 35% lower for giardiasis, 4640% greater for cryptosporidiosis, 61,900% greater for E.
Coli, and 96,200% greater for campylobacteriosis.
Health risk and source water quality of drinking water systems on BWAs
determined using QMRA model.
Numerical results representing weighted mean values of the derived probability distribution functions for the two scenarios modeled (confirmed cases of enteric illness and high estimate of actual cases of enteric illness) using the Health Canada QMRA
Model can be found in Table 17 for the aggregated population in the province on a BWA.
The probability distribution function graphs of DALY risk can be found in Figure 5 and BOIL WATER ADVISORIES & HEALTH RISK IN NL 68 Table 15
High and low estimate of average actual number of cases of enteric illness in Newfoundland and Labrador
High estimate Low estimate Average number of Number Number laboratory Number of actual Number of actual confirmed Number of actual cases Number of actual cases non- of actual cases minus of actual cases minus outbreak cases minus travel, cases minus travel, cases Number minus travel & food & Number minus travel & food & (1979- of actual travel food private of actual travel food private Waterborne Illness 2011) cases cases cases supplies cases cases cases supplies Giardiasis 40.2 1206 1110 1032 691 229 211 127 85 Cryptosporidiosis 1.4 9.4 8.6 7.9 5 9.4 8.6 7.7 5 Campylobacteriosis 80.5 3942 3154 473 317 1850 1480 44 30 E. Coli 5.4 255 245 184 123 54 52 21 14
BOIL WATER ADVISORIES & HEALTH RISK IN NL 69
Table 16
Comparison of calculated cases of enteric illness versus confirmed cases of enteric illness
Total number of illnesses per year QMRA model results Average population Average number Average on BWA without of non-outbreak High population on disinfection and in laboratory estimate of Average population BWA without non-compliance Waterborne Illness confirmed cases actual cases on a BWA disinfection with BWA Cryptosporidiosis 1.4 5 1305 447 237 Giardiasis 40.2 691 2472 848 449 Campylobacteriosis 80.5 317 1,679,759 576,014 305,287 Verotoxigenic E. Coli 5.4 123 419,658 143,907 76,271 Note. Average population on a BWA of 48,942. BOIL WATER ADVISORIES & HEALTH RISK IN NL 70
Table 17
QMRA model health risk of communities on BWAs using confirmed cases of enteric illness and high estimate of actual cases
Confirmed cases Average number of Probability of Exceeds laboratory Total # of illness per Annual DALY Health Canada confirmed illnesses per year risk risk level cases year (pop) (individual) (individual) # per 100 L (10 -6) Cryptosporidiosis 1.4 1.43 2.92E-05 4.96E-08 0.00064 No Giardiasis 40.2 40.4 0.000825 1.4E-06 0.048 Yes Campylobacterosis 80.5 80.8 0.00165 7.6E-06 0.0044 Yes Verotoxigenic E. Coli 5.4 5.5 0.000112 2.76E-06 0.042 Yes High estimate of actual cases Probability of Exceeds Total # of illness per Annual DALY Health Canada High estimate illnesses per year risk risk level of actual cases year (pop) (individual) (individual) # per 100 L (10 -6) Cryptosporidiosis 5 4.9 0.0001 1.7E-07 0.0022 No Giardiasis 691 690 0.0141 2.4E-05 0.82 Yes Campylobacterosis 317 312 0.00638 2.93E-05 0.017 Yes Verotoxigenic E. Coli 123 123 0.00252 6.18E-05 0.94 Yes Note. Average population on a BWA of 48,942; Health Canada risk level of 0.000001 DALYs. BOIL WATER ADVISORIES & HEALTH RISK IN NL 71
Figure 5. Probability distribution of DALY risk for confirmed cases of enteric illness.
Figure 6. Probability distribution of DALY risk for high estimate of actual cases of enteric illness. BOIL WATER ADVISORIES & HEALTH RISK IN NL 72
Figure 6. For both scenarios, Cryptosporidium levels do no exceed the Health Canada risk level guideline of 10 -6 DALYs per person per year. However, the guideline is
exceeded by Giardia , Campylobacter and E. coli . In the scenario using confirmed cases
of enteric illness, Campylobacter poses the greatest health risk. In the scenario using the
high estimate of actual cases of enteric illness, E. coli poses the greatest health risk.
Source water pathogen levels that give total number of illness per year comparable to
confirmed cases of enteric illness range from only 0.00064-0.048/100 L. Source water
pathogen levels that give total number of illness per year comparable to the high estimate
of actual cases of enteric illness range 3 times higher at the low end of the range to 20
times higher at the high end of the range.
Using QMRA to determine if the health risk warrants a BWA.
In the case of the BWA for Burgeo, no pathogens were detected in the tap water.
The drinking water system was being disinfected by chlorine, but there was insufficient
chlorine residual left in the distribution system according to provincial standards (0.10
mg/L detected and 0.30 mg/L required), triggering an automatic BWA. While there is no
source water pathogenic data for the Burgeo water supply, no E. coli has ever been detected in the tap water, giving some indication of the pristine nature of the source.
Levels for other pathogens were determined using Equations 1-3. For the remaining pathogens of interest, the health risk was well below the Health Canada risk level guideline of 10 -6 as indicated in Table 18 and Figure 7. Based on this assessment, the
health risk was not sufficient for issuing a BWA as the available treatment barriers (level BOIL WATER ADVISORIES & HEALTH RISK IN NL 73 of disinfection, available contact time) were enough to lower the risk posed by the low levels of pathogens in this pristine source.
In the case of the BWA for Mainland, E. coli was detected in the tap water. This distribution system has a history of tap water quality exceedances for E. coli , and the level detected on September 29, 2010 when the BWA was issued was 4000 CFUs/100 L.
While E. coli was detected in the tap water, a free chlorine residual of 0.08 mg/L was also detected in the distribution system. Back-calculating to take into account pathogen inactivation from chlorine disinfection, a source E. coli concentration of 18,400
CFUs/100 L was determined. This value is still lower than the average for positive results of 22,125 CFUs/100 L (see Table 8) detected in the tap water for this community.
Levels for other pathogens were determined using Equations 1-3. The health risk for
Campylobacter and E. coli was below the Health Canada risk level guideline of 10 -6 due to the presence of low levels of chlorine disinfectant in the drinking water system, however Giardia exceeded the guideline as indicated in Table 18 and Figure 8. Based on this assessment, the health risk was sufficient for issuing a BWA.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 74
Table 18
QMRA Model inputs and outputs for Burgeo and Mainland 2010 BWAs
Community Burgeo Mainland Population (2011 census or at time of outbreak) 1464 341 Total # of illnesses per year (population)- Cryptosporidium - - Total # of illnesses per year (population)- Giardia 0.0018 22.8 Total # of illnesses per year (population)- Campylobacter 0.00013 0.0022 Total # of illnesses per year (population)- E. coli - 0.000155 Total # DALY's per year (population)- Cryptosporidium - - Total # DALY's per year (population)- Giardia 3.04E-06 0.0388 Total # DALY's per year (population)- Campylobacter 6.01E-07 1.01E-05 Total # DALY's per year (population)- E. coli - 3.80E-06 Probability of illness per year (individual)- Cryptosporidium - - Probability of illness per year (individual)- Giardia 1.22E-06 0.0726 Probability of illness per year (individual)- Campylobacter 8.93E-08 7.02E-06 Probability of illness per year (individual)- E. coli - 4.93E-07 Annual DALY risk (individual)- Cryptosporidium - - Annual DALY risk (individual)- Giardia 2.08E-09 0.000124 Annual DALY risk (individual)- Campylobacter 4.11E-10 3.22E-08 Annual DALY risk (individual)- E. coli - 1.21E-08 Note. “-” indicates values were not obtained. BOIL WATER ADVISORIES & HEALTH RISK IN NL 75
Figure 7. Probability distribution of DALY risk for Burgeo BWA issued May 7, 2010.
Figure 8. Probability distribution of DALY risk for Mainland BWA issued September 29, 2010.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 76
Chapter 5: Discussion
Effects of Data Limitations on Results
Health Canada recommends a minimum of two years of monthly source water microbiological data in order to undertake QMRA. Source water quality data for microbiological parameters is not collected systematically in Newfoundland and
Labrador. What limited data exists is only for E. coli , Giardia and Cryptosporidium .
Larger systems, or systems with water treatment facilities, tend to have more comprehensive datasets than smaller communities that are more likely to be on BWAs.
Barriers to source water sampling for microbiological parameters include the cost of sample analysis, logistics of sample collection and transport, and perceived lack of need.
Giardia/Cryptosporidium analysis costs over $500 per sample from an accredited laboratory in Canada (as of 2012) using the standard USEPA Method 1623. This method also experiences variable recovery rates of target organisms (USEPA, 2005). Special samples collected by the province in 2012 had average recovery rates quoted by the laboratory of 46% and 42% for Cryptosporidium and Giardia respectively.
As stated in Chapter 3, in the absence of source water quality data for microbiological parameters, tap E. coli was used instead of source E. coli . Tap E. coli was also used to help determine levels of other microbiological parameters using
Equations 1-3. Where comparisons could be made between average ambient source water E. coli and tap water E. coli , source water values were on average 3.8 times greater.
This reflects the effectiveness of even limited amounts of chlorine disinfection in distribution systems in reducing E. coli levels. Using tap water E. coli as the basis for BOIL WATER ADVISORIES & HEALTH RISK IN NL 77
source water pathogen levels is likely to have underestimated source pathogen levels and
the health risk determined using QMRA.
However, for the estimates of Cryptosporidium and Giardia , the possibility of
underestimates is reduced since available data indicates no Cryptosporidium has been found in the province other than that reported by Wallis et al. (1996), and the majority of
Giardia samples collected have been non-detects. Going back to 1979, there has never been greater than 0.060 cases per 10,000 people for cryptosporidiosis in any given year, further indication of low concentrations of Cryptosporidium in drinking water sources.
The maximum number of epidemiological confirmed cases of associated illness for giardiasis over the period of record is 3.7 per 10,000 people, indicating the presence of
Giardia at higher levels, but not in abundance. Lacking more precise data, the estimation method used to determine source water pathogen levels appear to be reasonable.
It is generally accepted that infectious disease surveillance underestimates the level of disease in a population. Based upon this understanding, estimates of actual cases of local waterborne illness from public drinking water systems were made. With the last documented waterborne outbreak in the province occurring in 2002, the epidemiological data post-2002 is assumed to characterize endemic levels of enteric disease occurrence.
Since 2006, cases of waterborne disease have occurred in all regions of the province
(Eastern, Central, Western, Labrador), with the exception of no cryptosporidiosis cases ever detected in Central, further supporting the endemic and sporadic nature of recent epidemiological data. The assumption has been made by managers of drinking water quality in the province that communities on BWAs are contributing to endemic and BOIL WATER ADVISORIES & HEALTH RISK IN NL 78 sporadic levels of enteric disease occurrence in the province, however, more specific data is needed to confirm this.
QMRA model structure.
Output from Health Canada’s QMRA Model (version 11_07) includes a probability distribution for risk that provides a range of values that denote the uncertainty and variability of the input quantities and assumptions of the characterized risk. Health risk PDFs can extend over two orders of magnitude. Numerical results actually represent weighted mean averages. An understanding of the inherent uncertainty and variability in
QMRA is necessary for risk assessment, management and decision making. Changing one variable, water consumption, resulted in increases in the total number of cases of illness by over 400% for some pathogens.
Imbedded within the QMRA Model are several equations and constants taken from the literature (see Appendix D). For example, the probability of infection is calculated using dose-response equations from models reported in the literature, usually based on human experimental data or from disease outbreaks (Health Canada, 2011e).
The probability of illness, given infection is also calculated using values derived from literature, usually based on illness rates observed during disease outbreaks (Health
Canada, 2011e). The calculation for probability of annual illness does not account for any acquired immunity in the population and allows multiple illnesses to re-occur at high dose exposures (Health Canada, 2011e). In other words, the QMRA Model is structured towards outbreak rather than endemic conditions which may result in an overestimation of health risk. BOIL WATER ADVISORIES & HEALTH RISK IN NL 79
Characteristics of Communities on a BWA
The results show that small drinking water systems, communities with low economic capacity, LSDs, communities without disinfection systems, and communities without certified drinking water system operators are all factors significantly associated with a drinking water system being on a BWA. Having low levels of THMs and HAAs is also associated with being on a BWA. This is reasonable as drinking water systems without chlorine disinfection cannot produce THMs or HAAs, and groundwater systems that lack precursor material to form disinfection by-products (DBPs), such as THMs and
HAAs, often act as water sources for small systems more prone to being on BWAs. Lack of a disinfection system and certified operator also reflect on the economic capacity of the community, which in turn reflects on the size of the community.
Of the factors that were significantly correlated to the length of time a drinking water system spent on a BWA, the only unusual finding was that the season the BWA was issued affected the length of the BWA, with BWAs issued in the summer and fall lasting longer. One possible explanation for this is that operators tend to have more issues with water quality and operation of disinfection systems at this time of year. The lack of significant correlation between the length of time a system spends on a BWA and economic capacity of the community, governance structure of the community, and population serviced was also surprising, especially as these factors did correlate with whether a drinking water system is on a BWA or not. This indicates that while small, low economic capacity LSDs are more likely to be on a BWA, they are just as likely to come off of one as larger, richer municipalities. BOIL WATER ADVISORIES & HEALTH RISK IN NL 80
BWAs and Health Risk
Results indicated that there is no correlation between cases of possible waterborne
enteric illness and the annual number of BWAs, the population affected by BWAs, the
cumulative number of days communities spent on BWAs, or the percentage of BWAs
due to microbiological exceedances. Based on this analysis, BWAs do not accurately
reflect the health risk posed by waterborne pathogens in public drinking water systems.
However, the dataset involved was not extensive and the number of confirmed cases of
illness attributable to public drinking water systems was unknown.
Besides aggregated data on BWAs and aggregated data on cases of possible
waterborne enteric illness, there were limited datasets available to demonstrate any
further relationship between BWAs and waterborne disease. Based on limited evidence,
it appears that attack rates during waterborne outbreaks are less if BWAs are issued and
maintained until effective treatment is introduced to the drinking water system. From
information in Table 4, it is known that BWAs were issued for at least 3 of the 10
observed outbreaks; record keeping from this period was not consistent. Of the outbreaks
with attack rate information, it is important to note that there was a BWA issued for the
outbreak with the lowest attack rate.
Wallis et al. (1996) published Giardia counts of raw water samples that were
collected during outbreaks in the communities of Corner Brook (1992) and Botwood
(1991). The average Giardia count during the Corner Brook outbreak in 1992 was 0.6 cysts/100 L with a range of 0.5 - 0.7 cysts/100 L (Wallis et al., 1996). The QMRA
Model back-calculated source Giardia to be 3.4 cysts/100 L based on suspected cases of BOIL WATER ADVISORIES & HEALTH RISK IN NL 81 illness during the outbreak. The average Giardia count during the Botwood outbreak in
1991 was 2 cysts/100 L with a range of 0.2 - 6 cysts/100 L (Wallis et al., 1996). The
QMRA Model back-calculated source Giardia to be 36 cysts/100 L based on suspected cases of illness during the outbreak. In both cases, the QMRA Model result is off by an order of magnitude. However, given the accuracy of this older analytical method used by
Wallis et al. (1996) and the reported recovery rates (2-47% for Giardia ), the QMRA
Model back-calculated Giardia results seem reasonable.
Based on site-specific tap water quality data for E. coli , and established relationships between E. coli and other key pathogens ( Giardia , Cryptosporidium and
Campylobacter ), health risk was modeled using the QMRA Model for 12 representative communities on BWAs. The calculated average probability of illness per year in an individual for cryptosporidiosis and giardiasis was 0.27 and 0.51, respectively. Given the average population on a BWA since 2002 is 48,900, this translates into 1300 cases of cryptospiridosis and 2500 cases of giardiasis per year. These estimates are approximately
960 and 60 times greater than the number of confirmed cases observed in the province, respectively. The average calculated probability of illness per year in an individual for campylobacteriosis and verotoxigenic E. coli is 34.0 and 8.6 respectively. This translates into 1,680,000 cases of campylobacteriosis and 420,000 cases of verotoxigenic E. coli .
These estimates are approximately 21,000 and 78,000 times greater than the number of confirmed cases in the province respectively. The QMRA Model is overestimating the cases of illness based on the data input and assumptions that were made. BOIL WATER ADVISORIES & HEALTH RISK IN NL 82
There are many reasons for the estimated number of cases of enteric illness
examined to be different from the actual number of confirmed cases including: i)
residents on BWA are boiling their drinking water and killing off enteric pathogens prior
to consumption; ii) communities on BWAs may still be disinfecting drinking water (to an
insufficient degree for regulatory purposes) resulting in some level of log-inactivation of
pathogens not captured by the model, particularly for bacteriological pathogens
(Campylobacter and E. coli ) which are more easily inactivated by chlorine disinfection commonly used in the province; iii) local residents may have acquired some level of immunity to pathogens in drinking water; iv) large numbers of cases of gastrointestinal illness are not diagnosed as confirmed cases of enteric waterborne illness; v) local residents do not drink tap water; and, vi) Cryptosporidium and E. coli does not appear to be as widespread in the province as in other jurisdictions most likely due to the lack of agricultural activity and large numbers of cattle and other grazing animals used in food production, and the lack of sewage inputs into fresh waterbodies used for drinking water.
In fact, Newfoundland and Labrador is consistently below the national average for confirmed cases of cryptosporidiosis, verotoxigenic E. coli , giardiasis and campylobacterosis (Public Health Agency of Canada, 2006).
The number of confirmed cases of enteric illness does not match the total number of illnesses per year in the population affected by BWAs according to QMRA model results. Another of the reasons for this observed inaccuracy is that confirmed cases do not reflect the actual number of cases. The estimate of actual cases (high and low estimates) of waterborne enteric illness from local public drinking water systems to BOIL WATER ADVISORIES & HEALTH RISK IN NL 83
confirmed cases for giardiasis, cryptosporidiosis, campylobacteriosis and verotoxigenic
E. coli was 2.1 - 7, 3.5, 0.4 - 5.9, and 2.6 - 22 times greater, respectively. Factors from
the literature used to estimate actual cases of E. coli may not be reflective of conditions found in the province. There is still a significant difference in results from the QMRA
Model and revised estimates of actual waterborne illness for cryptosporidiosis, campylobacteriosis and verotoxigenic E. coli . However, after corrections (only looking at the population without disinfection and non-compliant with BWAs), QMRA Model results for giardiasis do closely match the revised high estimate of actual cases.
The health risk posed to all communities collectively on a BWA was back- calculated based on average, non-outbreak confirmed cases of enteric illness and the high estimate of actual local cases of waterborne enteric illness on public drinking water supplies. The annual DALY health risk back-calculated based on the high estimate of actual cases was 1.7x10 -7, 2.4x10 -5, 2.93x10 -5 and 6.18x10 -5 for Cryptosporidium ,
Giardia , Campylobacter and E. coli , respectively. Annual DALY health risk averaged
over the 12 communities, representative of different types of BWAs was 4.53x10 -5,
8.6x10 -5, 0.158 and 0.21 for Cyptosporidium , Giardia , Campylobacter and E. coli , respectively (using data from Table 14). The only pathogen for which DALY health risk was in the same order of magnitude was for Giardia . The results suggest that in Health
Canada’s QMRA Model, constants used for Giardia most closely reflect conditions found on the ground in Newfoundland and Labrador over other pathogens.
Source water pathogen concentrations based on tap water data appear to overestimate health risk particularly for Campylobacter and E. coli . Average source BOIL WATER ADVISORIES & HEALTH RISK IN NL 84
water pathogen concentrations used for the 12 communities representative of different
types of BWAs were 0.6 oocysts/100 L, 2.9 cysts/100 L, 587 CFUs/100 L and 5608
CFUs/100 L for Cryptosporidium , Giardia , Campylobacter and E. coli , respectively. E. coli values were taken from tap water quality samples and are less than what would be typically found in corresponding source waters. Giardia levels of 2.9 cysts/100 L have been observed in source waters in Newfoundland and Labrador, with a current documented range of 0 - 6 cysts/100 L. Wallis et al. (1996) indicated that less than 10% of 195 samples from the province tested positive for Cryptosporidium and that most positive results were at concentrations of 0.5 oocysts/100 L. Results from other sources of Cryptosporidium source sampling in the province have all been 0 oocysts/100 L.
There is no information on source water Campylobacter concentrations in the province.
Based on known data, the average source water pathogen concentrations from the 12 communities is overestimated for Cryptosporidium and Giardia and underestimated for
E. coli .
Looking at all communities on BWAs as one theoretical community, the back- calculated source water pathogen concentrations using QMRA, based on the high estimate of actual enteric illness, were 0.0022 oocysts/100 L, 0.82 cysts/100 L, 0.017
CFUs/100 L and 0.94 CFUs/100 L for Cryptosporidium , Giardia , Campylobacter and E. coli , respectively. Except for Giardia , these concentrations are two or more orders of magnitude smaller than those based on tap water data. The relationships between typical source water pathogen concentrations used in the QMRA Model do not appear accurate for conditions in Newfoundland and Labrador except for Giardia . BOIL WATER ADVISORIES & HEALTH RISK IN NL 85
The largest number of confirmed cases of illness is for campylobateriosis
followed by giardiasis, verotoxigenic E. coli and Cryptosporidium . In terms of DALY health risk, however, giardiasis ranks below both campylobacteriosis and verotoxigenic
E. coli . In the scenario based on confirmed cases of illness, Campylobacter displays the highest health risk. In the scenario based on the high estimate of actual cases, E. coli displays the highest health risk. While several Giardia outbreaks have occurred in the province in the past, and there were more cases of giardiasis in both scenarios, the DALY health risk of E. coli is still of greater concern according to the QRMA model. Factors used to estimate actual cases of E. coli used in this scenario may not be as applicable to conditions in Newfoundland and Labrador, further inflating the health risk from E. coli .
To be an effective tool, the QMRA Model results of the 12 representative communities on BWAs should reflect the level of health risk posed by waterborne pathogens to communities on BWAs. In comparing these results to confirmed cases of illness and high estimates of actual waterborne illness, it appears that endemic health risk is overestimated using QMRA. The modeled and actual health risk is complicated by numerous factors including compliance with BWAs, use of alternative sources of drinking water (e.g., bottled water), immunity to local pathogens, under reporting of illness, maintenance of low or sporadic levels of disinfection in the drinking water system, variability in source water pathogen concentrations, lack of pathogen sources (eg. sewage inputs, agricultural inputs), the structure of the QMRA model, and constants used in the QMRA Model.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 86
Using Health Risk to Determine if BWAs are Warranted
QMRA provides a quantitative approach to determining whether to issue a BWA
or not. In examining two BWAs in the province issued in 2010, QMRA determined that
there was no significant health risk associated with one of the BWAs based on a health
risk guideline of 10 -6 DALYs. It is probable that based on this type of QMRA assessment, up to 20% of active BWAs (half of BWAs issued for residual chlorination problems) would meet the health risk guideline of 10 -6 DALYs. Health risk associated
with BWAs because of residual chlorination problems and operational problems with the
distribution system may be lower than for other types of BWAs (e.g., no disinfection,
microbiological exceedances).
Policy Implications of Results
The results of this study have various implications in terms of possible policy
outcomes for drinking water management. Newfoundland and Labrador’s current BWA
policy takes a zero-risk tolerance approach; if there is any perceived risk to the drinking
water a BWA is called. The overuse of BWAs is problematic from a risk communication
and message fatigue standpoint. It is also inefficient from a risk management standpoint.
If the province is to adopt a more nuanced risk tolerance approach as part of a new BWA
policy it must be protective of public health. No one wants to see a slackened policy be
responsible for an outbreak of waterborne illness. Basing BWAs on quantifiable health
risk using QMRA ensures that each system is individually evaluated, that nationally
prescriptive health risk targets are met, and that there is no room for ambiguity or BOIL WATER ADVISORIES & HEALTH RISK IN NL 87 interpretation if BWA criteria are based on qualitative factors. As it is currently set up, the Health Canada QMRA Model also tends to overestimate health risk for the province.
The value of BWAs as a public health risk management tool in non-outbreak conditions is questionable. No correlation was detected between cases of waterborne illness and different BWA related factors. BWAs are issued if there is any possible risk of pathogenic contamination, however, the health risk associated with each type of
BWAs and in each individual community varies considerably. As a blanket approach to risk management, BWAs do not accurately reflect health risk. While endemic rates of waterborne illness have predominated in the province for the past decade, the fear of a future outbreak and the reliance on calling a BWA as sufficient action, allows for no nuance for addressing various levels of health risk within drinking water advisory protocols.
The decision making process for issuing BWAs in Newfoundland and Labrador is black and white – if there is confirmed microbiological contamination (total coliforms or
E. coli ) or the possible risk of microbiological contamination, a BWA is issued. Other jurisdictions are taking a qualitative risk assessment approach based on a number of factors (source water quality, activity in the source area, treatment, mitigative actions, level of operator competency, etc.) before issuing a BWA. Better decision-making on the issuing of BWAs that accounts for variations in health risk, and that is not based on value judgements of various factors, provides a scientifically feasible and practical option for issuing BWAs in the province. BOIL WATER ADVISORIES & HEALTH RISK IN NL 88
The regulatory framework for drinking water does not necessarily work for small communities. The systemic cause of why certain communities are on BWAs is a lack of resources (financial, technical and human). Until this issue is addressed, the problem of
BWAs in these under-resourced communities will continue.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 89
Chapter 6: Conclusions and Recommendations
The specific research objectives identified for this thesis were to identify characteristics of significance for communities on BWAs, evaluate the health risk posed by drinking water systems on BWAs, and make policy recommendations for an improved drinking water advisory framework and the management of small drinking water systems.
It is hoped that the conclusions from this study can be used to support further policy, programs and actions to help reduce the number of BWAs, and increase drinking water safety in Newfoundland and Labrador.
Conclusions
Characteristics of communities on BWAs.
In Newfoundland and Labrador, small drinking water systems without certified operators, mostly in LSDs with low economic capacity, are more likely to be on BWAs.
From these findings the conclusion is that being able to identify common characteristics of communities on BWAs will enable policy and programs to help address this issue. Another possible option in dealing with BWAs is to implement safe levels of variance from requirements for small systems.
Health risk posed by BWAs.
QMRA as applied to drinking water is a relatively new tool, and its applications are still being investigated. In this study, QMRA was used to explore the accuracy of
BWAs issued in Newfoundland and Labrador to reflect health risk, and whether that health risk warranted a BWA based on the Health Canada health risk target of 10 -6 BOIL WATER ADVISORIES & HEALTH RISK IN NL 90
DALYs per person per year. The Health Canada QMRA Model used in this study appears to be calibrated towards outbreak conditions, larger systems, and water sources with higher levels of microbiological contamination than commonly found in the province. As such, the model tended to overestimate health risk when compared to epidemiological cases of enteric illness.
The structure of the Health Canada QMRA Model, however, allows many of these constants to be user selected. In order to fine tune the QMRA Model for use in assessing the health risk for issuing BWAs, the model should be calibrated towards endemic conditions, smaller systems, and typical source water pathogens for
Newfoundland and Labrador. A closer look at two specific BWAs indicated that health risk as determined using the QMRA Model was low enough to not have warranted a
BWA in the community of Burgeo, while in the case of Mainland a BWA was appropriate.
From these findings the conclusion is that QMRA can be integrated into a new drinking water advisory framework based on improved risk assessment, communication and management. In moving from a zero-risk tolerance policy for issuing BWAs to a site and time specific, quantitative health risk assessment policy, there will be several collateral benefits: i) the number of active BWAs in the province will be culled with the removal of certain types of BWAs where health risk guidelines are met; ii) QMRA health risk information could be communicated as part of the BWA to more effectively relay potential consequences of non-compliance with the BWA; and iii) as BWAs will be BOIL WATER ADVISORIES & HEALTH RISK IN NL 91 issued with more circumspection, their issuance will be taken more seriously by residents which will influence greater compliance rates.
Recommendations
Policy recommendations.
The following is a list of policy recommendations and specific actions to be taken to reduce the number of BWAs in the province of Newfoundland and Labrador and to develop an improved drinking water advisory framework based on QMRA:
1. Newfoundland and Labrador should consider adopting a quantitative health risk
assessment framework using QMRA for the issuing of BWAs.
2. Newfoundland and Labrador should consider adopting the Health Canada health
risk target of 10 -6 DALYs per person per year for individual pathogens as a
guideline or standard for drinking water safety.
3. Training should be provided on using QMRA to determine health risk to those in
the province who make decisions on whether to issue BWAs.
4. The province should consider developing a source water microbiological
sampling program in order to determine background concentrations of pathogens.
Sampling should be undertaken for Cryptosporidium , Giardia , Campylobacter ,
and E. Coli . Other possible waterborne pathogens causing enteric illness could be
considered for sampling and analysis as long as there is corresponding
epidemiological data. Sampling frequency should follow USEPA rules of two
years of monthly sampling in order to determine background levels for all public
drinking water sources. High risk, impaired, or water sources with high levels of BOIL WATER ADVISORIES & HEALTH RISK IN NL 92
development activity should be given priority for sampling. Sampling should not
be undertaken at a frequency of less than quarterly. Samples should be identified
as event based if taken after heavy rainfall or snowmelt, and nominal if taken
during dry conditions to facilitate hazard identification of higher risk events.
5. Using pathogen concentration data collected from source waters in Newfoundland
and Labrador, the province should develop typical ranges for source water
pathogen concentrations for pristine, lightly impacted, moderately impacted, and
highly impacted source waters.
6. In order to prevent towns with characteristics that commonly lead to BWAs from
going on BWAs, the province should consider implementing preventative policy
options such as:
a) targeted training of small water system operators,
b) government grants for small system operator wages,
c) regionalization of small communities,
d) regionalizing drinking water services,
e) regional drinking water system operators,
f) preferential capital cost funding ratios for small drinking water system
infrastructure,
g) switching from supply side treatment to demand side treatment with point
of use/point of entry devices by homeowners for small drinking water
systems, BOIL WATER ADVISORIES & HEALTH RISK IN NL 93
h) changing the governance structure for municipalities, LSDs and
unincorporated communities in the province,
i) government funding for operation and maintenance of drinking water
systems,
j) introduce penalties for communities that do not disinfect their drinking
water, and
k) introduce incentives for communities to disinfect their drinking water and
stay off of BWAs.
7. When microbiological field sampling for E. coli is undertaken, data should also be
collected on water pH, water temperature, and flows (instantaneous and daily) in
the distribution system for input into Health Canada’s QMRA Model. The
province should also develop a database of pipe diameter, pipe length and storage
volumes for each public drinking water system up to the first point of use in order
to calculate contact time for input into the QMRA Model.
8. The provincial Public Health Laboratory should consider developing in-house
polymerase chain reaction (PCR) analysis methods for the rapid and efficient
detection of pathogens in drinking water sources over classical detection methods.
9. In addition to constants used for outbreak situations, the province should develop
epidemiological constants that reflect endemic disease rates in the province for
dose-response equations that calculate the probability of infection, and the
probability of illness given infection. BOIL WATER ADVISORIES & HEALTH RISK IN NL 94
10. A calibration step using epidemiological data should be incorporated into QMRA
modelling.
11. The Section on Drinking Water Exposures in the provincial Foodborne/
Waterborne Illness Investigation report form should include a question on
whether your drinking water supply was under a BWA. Data from these reports
should be entered into a digital database.
Recommendations for future research.
This study reveals fault lines with respect to which communities end up on BWAs in Newfoundland and Labrador and which do not. It also investigates the decision- making process behind issuing BWAs in the province and makes recommendations for a new approach. The work undertaken in this study also provides an impetus for further research. Areas for further research that have emerged as part of this study include:
1. The role of BWAs in controlling, or not, enteric waterborne disease in the
province needs to be examined more closely. More data with sufficient
specificity needs to be collected to more accurately test the connection between
BWAs, waterborne disease outbreaks, and endemic levels of enteric waterborne
disease.
2. A population-based study of gastrointestinal illness should be conducted on
communities in the province with long-term BWAs, short-term BWAs, and not on
a BWA to determine prevalence, incidence rates, probability of illness, and
duration of illness. As gastrointestinal illness is not considered a notifiable BOIL WATER ADVISORIES & HEALTH RISK IN NL 95
disease by the province, such a study would provide a more complete picture of
likely health effects posed by BWAs.
3. Examining the link between the characteristics of communities on BWAs and the
health risk posed by the BWA to determine if certain characteristics are more
significantly associated with a high level of health risk. Greater understanding of
these associations could assist with any qualitative risk assessment of whether a
BWA is warranted or not and can further reinforce the results of the quantitative
risk assessment using QMRA. This work could also include an evaluation of the
health risk associated with different types of BWAs.
4. A longitudinal study of BWAs in small systems that follows the BWA from the
time of issue, including how the BWA is communicated to the public,
epidemiological consequences, rates of public compliance, rates of change in
public compliance over time, residents coping behaviours, and effectiveness of
corrective actions. Such a study would provide much needed understanding of
the mechanics of how a BWA affects small drinking water systems.
BOIL WATER ADVISORIES & HEALTH RISK IN NL 96
References
American Water Works Association. (2012, November 19). Washington report –
November 2012 . Retrieved from http://www.awwa.org/legislation-regulation/leg-
reg-news-details/articleid/322/washington-report-november-2012.aspx
Battcock, T. (2009). Bacteriological monitoring [PowerPoint slides]. Retrieved from
http://www.env.gov.nl.ca/env/waterres/training/adww/ruralreactions/02b_terry_ba
ttcock_dwl_monitoring.pdf
Butt, K. D. (2010). Perceptions of public drinking water in Newfoundland and
Labrador: A mixed methods study (Master’s thesis). Available from ProQuest
Dissertations and Theses database. (UMI No. MR68927)
Centers for Disease Control and Prevention. (2010). Cryptosporidiosis Surveillance-
United States, 2006–2008 and Giardiasis Surveillance-United States, 2006–2008.
Surveillance Summaries. Morbidity and Mortality Weekly Report, 59 (No. SS-6).
Retrieved from http://www.cdc.gov/mmwr/pdf/ss/ss5906.pdf
Charrois, J. (2010). Private drinking water supplies: Challenges for public health.
Canadian Medical Association Journal, 182 (10), 1061-1064. doi:
10.1503/cmaj.090956
Council of the Federation Secretariat. (2013). Toolbox of Regulatory and Non-Regulatory
Options for Small Drinking Water Systems . Manuscript in preparation.
Department of Environment and Conservation, Water Resources Management Division.
(2002). Source to Tap: Water Supplies in Newfoundland and Labrador . Retrieved
from http://www.env.gov.nl.ca/env/waterres/reports/source_to_tap/index.html BOIL WATER ADVISORIES & HEALTH RISK IN NL 97
Department of Environment and Conservation, Water Resources Management Division.
(2003). Drinking water safety in Newfoundland and Labrador: Annual report
2002 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
2.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2004). Drinking water safety in Newfoundland and Labrador: Annual report
2003 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
3.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2005a). Drinking water safety in Newfoundland and Labrador: Annual report
2004 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
4.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2005b). Guidelines for the Design and Operation of Water and Sewerage
Systems . Retrieved from
http://www.env.gov.nl.ca/env/waterres/waste/groundwater/guidelines_for_design
_constr_oper_wss.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2006). Drinking water safety in Newfoundland and Labrador: Annual report BOIL WATER ADVISORIES & HEALTH RISK IN NL 98
2005 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
5.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2007). Drinking water safety in Newfoundland and Labrador: Annual report
2006 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
6.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2008a). Drinking water safety in Newfoundland and Labrador: Annual report
2007 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
7.pdf
Department of Environment and Conservation, Water Resources Management Division.
(July 2, 2008b). Bacteriological quality of drinking water . Retrieved form
http://www.env.gov.nl.ca/env/waterres/regulations/policies/standards_microbiolo
gical.html
Department of Environment and Conservation, Water Resources Management Division.
(2009). Drinking water safety in Newfoundland and Labrador: Annual report
2008 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
8_final.pdf BOIL WATER ADVISORIES & HEALTH RISK IN NL 99
Department of Environment and Conservation, Water Resources Management Division.
(2010a). Drinking water safety in Newfoundland and Labrador: Annual report
2009 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
9.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2010b). Study on operation and maintenance of drinking water infrastructure in
Newfoundland and Labrador . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/operation_and_mai
ntenance_study_055425_rpt7_final_v2.pdf
Department of Environment and Conservation, Water Resources Management Division.
(2011a). Drinking water safety in Newfoundland and Labrador: Annual report
2010 . Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_200
9-10.pdf
Department of Environment and Conservation, Water Resources Management Division.
(October 12, 2011b). Boil water advisory fact sheet . Retrieved form
http://www.env.gov.nl.ca/env/waterres/quality/drinkingwater/advisory_fact_sheet
.html
Department of Environment and Conservation, Water Resources Management Division.
(2012a). Drinking water safety in Newfoundland and Labrador: Annual report
2011. Retrieved from BOIL WATER ADVISORIES & HEALTH RISK IN NL 100
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/Drinking_Water_S
afety_Annual_Report_2011.pdf
Department of Environment and Conservation, Water Resources Management Division.
(April 2, 2012b). Boil water advisories . Retrieved form
http://www.env.gov.nl.ca/env/waterres/quality/drinkingwater/advisories.html
Department of Environment and Conservation, Water Resources Management Division.
(2013). Drinking water safety in Newfoundland and Labrador: Annual report
2012. Retrieved from
http://www.env.gov.nl.ca/env/waterres/reports/drinking_water/annual_report_201
2.pdf
Department of Health and Community Services, Disease Control and Epidemiology
Division. (2003). Boil water advisory guidelines . Unpublished manuscript.
Department of Health and Community Services. (2011a). Newfoundland and Labrador
disease control manual section 2: Enteric food and waterborne diseases .
Retrieved from
http://www.health.gov.nl.ca/health/publications/diseasecontrol/s2_enteric_food_a
nd_waterborne_diseases.pdf
Department of Health and Community Services. (2011b). Communicable disease report-
quarterly, 28 (3). Retrieved from
http://www.health.gov.nl.ca/health/publichealth/cdc/mdr/cdr_v28n3_dec2011.pdf
Department of Health and Community Services. (2013). Surveillance and disease
reports . Retrieved from BOIL WATER ADVISORIES & HEALTH RISK IN NL 101
http://www.health.gov.nl.ca/health/publichealth/cdc/informationandsurveillance.h
tml
Edwards, J.E., Henderson, S.B., Struck, S., & Kosatsky, T. (2012). Characteristics of
small residential and commercial water systems that influence their likelihood of
being on drinking water advisories in rural British Columbia, Canada: a cross-
sectional study using administrative data. Journal of Water and Health, 10 (4),
629–649. doi: 10.2166/wh.2012.046
Eggertson, L. (2008). Investigative report: 1766 boil-water advisories now in place across
Canada. Canadian Medical Association Journal, 178 (10), 1261-1263.
doi:10.1503/cmaj.080525
Enger, K. S., Nelson, K. L., Clasen, T., Rose, J. B., & Eisenberg, J. N. S. (2012). Linking
quantitative microbial risk assessment and epidemiological data: Informing safe
drinking water trials in developing countries. Environmental Science &
Technology, 46 (9), 5160
Fraser Health Authority. (2007). Guideline: Issuing and Rescinding A Drinking Water
Public Notice . Environmental Health Services, Health Protection. Unpublished
manuscript.
Grier, K., & Schmidt, C. (2009). E. coli 0157 Risk Reduction: Economic Benefit to
Canada. George Morris Centre . Retrieved from
http://www.fightecoli.com/docs/GMC_Economic_Benefit_Report_October_2009.
pdf BOIL WATER ADVISORIES & HEALTH RISK IN NL 102
Grover, R. (2011). Boil, boil, toil and trouble: The trouble with boil water advisories in
British Columbia (Master’s thesis, University of British Columbia). Retrieved
from https://circle.ubc.ca/handle/2429/33790
Harding, A., & Anadu, E. (2000). Consumer response to public notification. Journal of
the American Water Works Association, 92 (8), 32-41.
Haas, C. N., Rose, J. B., & Gerba, C. P. (1999). Quantitative microbial risk assessment .
New York: Wiley.
Health Canada. (2001). North Battleford, Saskatchewan Spring, 2001Waterborne
Cryptospiridosis Outbreak . Retrieved from Health Canada website
http://www.health.gov.sk.ca/nb-waterborne-cryptodporidiosis-outbreak
Health Canada. (2009). Guidance for issuing and rescinding boil water advisories (HC
Publication No.: 4116). Retrieved from http://www.hc-sc.gc.ca/ewh-
semt/alt_formats/hecs-sesc/pdf/pubs/water-eau/boil_water-
eau_ebullition/boil_water-ebul_eau-eng.pdf
Health Canada. (2010). Enteric viruses in drinking water. Retrieved from http://hc-
sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/consult/_2010/enteric-
enteriques/enteric-enteriques-eng.pdfdf
Health Canada. (2011a). Enteric protozoa: Giardia and cryptosporidium . Retrieved from
http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-
sesc/pdf/consult/_2010/giardia-cryptosporidium/giardia-cryptosporidium-eng.pdf BOIL WATER ADVISORIES & HEALTH RISK IN NL 103
Health Canada. (2011b). Escherichia coli in drinking water . Retrieved from
http://www.hc-sc.gc.ca/ewh-
semt/alt_formats/pdf/consult/_2011/ecoli/ecoli-draft-ebauche-eng.pdf
Health Canada. (2011c). Total coliforms in drinking water . Retrieved from http://hc-
sc.gc.ca/ewh-semt/alt_formats/pdf/consult/_2011/coliform/total-coliforms-draft-
ebauche-eng.pdf
Health Canada. (2011d). Turbidity in drinking water . Retrieved from http://hc-
sc.gc.ca/ewh-semt/alt_formats/pdf/consult/_2011/turbidit/draft-ebauche-eng.pdf
Health Canada. (2011e). QMRA_CrypGiardiaRotaCampyEcoli (Version 11_07)
[software].
Health Canada. (2012). Guidelines for Canadian drinking water quality summary table .
Retrieved from http://hc-sc.gc.ca/ewh-semt/alt_formats/pdf/pubs/water-eau/2012-
sum_guide-res_recom/2012-sum_guide-res_recom-eng.pdf
Hrudey, S. (2011). Safe drinking water policy for Canada - turning hindsight into
foresight (Report No.: No. 323). Retrieved from C.D Howe Institute website:
http://www.cdhowe.org/pdf/Commentary_323.pdf
Hrudey, S.E., & Hrudey, E.J. (2004). Safe drinking water: Lessons from recent outbreaks
in affluent nations . London, UK: IWA Publishing.
Hrudey, S. E., Hrudey, E. J., & Pollard, S. J. T. (2006). Risk management for
assuring safe drinking water. Environment International , 32 (8), 948-957.
doi:10.1016/j.envint.2006.06.004 BOIL WATER ADVISORIES & HEALTH RISK IN NL 104
Jakopanec, I., Borgen, K., Vold, L., Lund, H., Forseth, T., Hannula, R., & Nygård, K.,
(2008). A large waterborne outbreak of campylobacteriosis in Norway: The need
to focus on distribution system safety. BMC Infectious Diseases,
8(128). doi:10.1186/1471-2334-8-128
Khan, R.A. (2001). Zoonoses and New Parasites in Canada. Proceedings of 1st Congress
of Federation of Asian Parasitologists.
Kot, M., Castleden, H., & Gagnon, G. A. (2011). Unintended consequences of regulating
drinking water in rural Canadian communities: Examples from Atlantic Canada.
Health and Place , 17 (5), 1030-1037. doi:10.1016/j.healthplace.2011.06.012
Mead, P. S., Slutsker, L., Dietz, V., McCaig, L. F., Bresee, J. S., Shapiro, C., Griffin,
P.M, & Tauxe, R.V. (1999). Food-related illness and death in the United States.
Emerging Infectious Diseases, 5 (5), 607- 625.
Medema, G., Ashbolt, N. (2006). QMRA: its value for risk management. Retrieved from
the European Commission MICRORISK website:
http://www.microrisk.com/uploads/microrisk_value_of_qmra_for_risk_managem
ent.pdf
Ministry of Health, Province of British Columbia. (2008). Turbidity and Microbial Risk
in Drinking Water . Retrieved from
http://www.health.gov.bc.ca/protect/pdf/TACsubmitted.pdf
Ministry of Environment, Province of Ontario. (2012). An overview of drinking water
system types regulated by the Ministry of the Environment . Retrieved from BOIL WATER ADVISORIES & HEALTH RISK IN NL 105
http://www.ene.gov.on.ca/environment/dwo/en/responsibilities/STDPROD_0959
58.html
Moffatt, H., & Struck, S. (2011). Water-borne Disease Outbreaks in Canadian Small
Drinking Water Systems. Retrieved from the National Collaborating Centers for
Public Health website: http://www.nccph.ca/docs/SDWS_Water-borne_EN.pdf
Monfared, S. (2010). Quantitative microbial risk assessment of Halifax drinking water
(Master’s thesis). Available from ProQuest Dissertations and Thesis database.
(UMI No. MR68127)
Nova Scotia Environment. (2013). Public drinking water supplies . Retrieved from
http://www.gov.ns.ca/nse/water/publicwater.asp
O’Connor, D. (2002). Report of the Walkerton inquiry: Part 1. The events of May 2000
and related issues . Retrieved from
http://www.attorneygeneral.jus.gov.on.ca/english/about/pubs/walkerton/part1/
Olsen, S.J., Miller, G., Breuer, T., Kennedy,M., Higgins,C., Walford, J., McKee, G., Fox,
K., Bibb, W., & Mead, P., (2002). A Waterborne Outbreak of Escherichia coli
O157:H7 Infections and Hemolytic Uremic Syndrome: Implications for Rural
Water Systems. Emerging Infectious Diseases, 8 (4), 370–375. doi:
10.3201/eid0804.000218
Payment, P. (2012). Assessing waterborne health risks through quantitative risk
assessment models. Retrieved from Canadian Water Network website:
http://www.cwn-rce.ca/research/core/pph-01/ BOIL WATER ADVISORIES & HEALTH RISK IN NL 106
Payment, P., & Pintar, K. (2006). Waterborne pathogens: A critical assessment of
methods, results and data analysis. Journal of Water Science , 19 (3), p. 233-245.
Petterson, S., Signor, R., Ashbolt, N., & Roser, D. (2006). QMRA methodology .
Retrieved from the European Commission MICRORISK website:
http://www.microrisk.com/uploads/microrisk_qmra_methodology.pdf
Pintar, K. D. M. (2008). Waterborne cryptosporidiosis: Adopting a mixed methods
approach to inform public health decision-making (Doctorate thesis). Available
from ProQuest Dissertations and Theses database. (UMI No. NR50137)
Public Health Agency of Canada. (2006). Notifiable disease on-line . Retrieved from the
Government of Canada website http://dsol-smed.phac-aspc.gc.ca/dsol-
smed/ndis/c_time-eng.php
Public Health Agency of Canada. (2010). National enteric surveillance program: Annual
summary 2009. Retrieved from : http://www.nml-lnm.gc.ca/NESP-
PNSME/assets/pdf/NESP_2009_Annual_Report_ENG.pdf
Roser, D., Petterson, S., Signor, R., Ashbolt, N., Nilsson, P., & Thorwaldsdotter, R.
(2006). How to implement QMRA to estimate baseline and hazardous event risks
with management end uses in mind. Retrieved from the European Commission
MICRORISK website:
http://www.microrisk.com/uploads/microrisk_how_to_implement_qmra.pdf
Rundblad, G., Knapton, O., & Hunter, P.R. (2010). Communication, perception and
behaviour during a natural disaster involving a ‘Do Not Drink’ and a subsequent BOIL WATER ADVISORIES & HEALTH RISK IN NL 107
‘Boil Water’ notice: a postal questionnaire study. BMC Public Health , 10 (1), 641-
641. doi:10.1186/1471-2458-10-641
Scallan, E., Hoekstra, R.M., Angulo, F.J., Tauxe, R.V., Widdowson, M.A., Roy, S.L.,
Jones, J.L., & Griffin, P.M., (2011). Foodborne illness acquired in the United
States—major pathogens. Emerging Infectious Diseases, 17 (1), 7-15.
doi:10.3201/eid1701.P11101. Retrieved from
http://dx.doi.org/10.3201/eid1701.P11101
Schijven, J. F., Teunis, P. F. M., Rutjes, S. A., Bouwknegt, M., & de Roda Husman,
A. M. (2011). QMRAspot: A tool for quantitative microbial risk assessment from
surface water to potable water. Water Research , 45 (17), 5564-5576.
doi:10.1016/j.watres.2011.08.024
Schuster, C., Aramini, J., Ellis, A., Marshall, B., Robertson, W., Medeiros, D., &
Charron, D. F., (2005). Infectious disease outbreaks related to drinking water in
Canada, 1974-2001. Canadian Journal of Public Health, 96 (4), 254-8.
Stalker, N., Sinclair, J., Medeiros, D., McFadyen, S., Neumann, N., Chen, M., &
Ruecker, N., (2012). QMRA: The City of Calgary Experience . [PowerPoint
slides]. Retrieved from http://www.cwn-rce.ca/assets/resources/pdf/QMRA-
Presentation-Nancy-1-FINAL.pdf
Strauss, B., King, W., Ley, A., & Hoey. J.R. (2005). A prospective study of rural
drinking water quality and acute gastrointestinal illness. BMC Public Health. 1(8).
doi:10.1186/1471-2458-1-8 BOIL WATER ADVISORIES & HEALTH RISK IN NL 108
Thomas, M.K., Majowicz, S.E., Sockett, P.N., Fazil, A., Pollari, F., Dore, K., Flint, J.A.,
& Edge, V.L., (2006). Estimated numbers of community cases of illness due to
Salmonella, Campylobacter and verotoxigenic Escherichia coli: Pathogen specific
community rates. Canadian Journal of Infections Diseases and Medical
Microbiology, 17 (4), 229-234.
Uhlmann, S., Galanis, E., Takaro, T., Mak, S., Gustafson, L., Embree, G., Bellack, N.,
Corbett, K., & Isaac-Renton, J. (2009). Where's the pump? Associating sporadic
enteric disease with drinking water using a geographic information system, in
British Columbia, Canada, 1996–2005. Journal of Water and Health , 7(4), 692–
698. doi:10.2166/wh.2009.108
United States Environmental Protection Agency. (2005). Method 1623: Cryptosporidium
and giardia in water by filtration/IMS/FA. (Report No.: EPA 815-R-05-002).
Retrieved from http://www.epa.gov/microbes/1623de05.pdf
United States Environmental Protection Agency. (2012a). LT2 Rule . Retrieved from
http://water.epa.gov/lawsregs/rulesregs/sdwa/lt2/regulations.cfm
United States Environmental Protection Agency. (2012b). Microbial risk assessment
guideline– Pathogenic microorganisms with focus on food and water . (Report
No.: EPA/100/J-12/001). Retrieved from http://www.epa.gov/raf/files/mra-
guideline-july-final.pdf
Wallis, P., Erlandsen, S., Isaac-Renton, J., Olson, M., Robertson, W., & van Keulen, H.
(1996). Prevalence of giardia cysts and cryptosporidium oocysts and BOIL WATER ADVISORIES & HEALTH RISK IN NL 109
characterization of giardia spp. isolated from drinking water in Canada. Applied
and Environmental Microbiology, 62 (8), 2789-2797.
Wallis, P. M., Matson, D., Jones, M., & Jamieson, J. (2001). Application of
monitoring data for Giardia and Cryptosporidium to boil water advisories. Risk
Analysis, 21 (6), 1077-1086. doi:10.1111/0272-4332.216176
World Health Organization. (2004). Guidelines for drinking water quality, 3rd edition .
Retrieved from
http://www.who.int/water_sanitation_health/dwq/GDWQ2004web.pdf
World Health Organization. (2011). Guidelines for drinking water quality, 4 th edition .
Retrieved from
http://whqlibdoc.who.int/publications/2011/9789241548151_eng.pdf
Wilson, J., Aramini, J., Clarke, S., Novotny, M., Quist, M., & Keegan, V. (2009).
Retrospective surveillance for drinking water-related illnesses in Canada, 1993-
2008: Final report . Retrieved from the National Collaborating Centre for
Environmental Health website
http://www.ncceh.ca/practice_policy/ncceh_reviews/dw_illnesses_surveillance .
BOIL WATER ADVISORIES & HEALTH RISK IN NL 110
Appendix A: Public Drinking Water Systems in Newfoundland and Labrador on
BWA as of March 31, 2012
BOIL WATER ADVISORIES & HEALTH RISK IN NL 111
COMMUNITY REASON ISSUED NUM POPULATION SERVICED AREA SOURCE NAME REASON REGION STATUS NAME CODE DATE DAYS SERVICED Admirals Beach Admiral's Beach 2 Well Fields Water Supply has no disinfection A 10/13/2010 537 185 E MUN system. Aquaforte Aquaforte Davies Pond Disinfection system is off, due to C1 6/23/2000 4301 46 E MUN maintenance or mechanical failure. Aquaforte Aquaforte Davies Pond Total coliforms detected and F3 6/23/2000 4301 46 E MUN confirmed in repeat sample. Baie Verte Baie Verte Baie Verte River Water entering distribution system E1 7/6/2009 1001 1275 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Baine Harbour Baine Harbour Baine Harbour Pond Chlorination system is turned off B3 6/1/1995 6150 74 E MUN by operator, due to lack of funds to operate. Baine Harbour Baine Harbour Dug Water Supply has no disinfection A 11/14/2003 3062 52 E MUN system. Bartletts Harbour Bartletts Harbour Long Pond (same as No free chlorine residual detected E2 4/29/1998 5087 136 W LSD Castors River in the water distribution system. North) Bay L'Argent Bay L'Argent Sugarloaf Hill Pond Water entering distribution system E1 6/2/2008 1400 255 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Bay de Verde Bay de Verde Island Pond Water distribution system is D1 3/22/2012 11 396 E MUN undergoing maintenance or repairs. Beachside Beachside Long Pond Disinfection system is off, due to C2 4/29/2011 339 174 C MUN lack of chlorine or other disinfectant. Bear Cove Bear Cove Lower Bear Cove No free chlorine residual detected E2 6/21/2000 4303 20 W LSD in the water distribution system. Bear Cove Bear Cove Upper Bear Cove No free chlorine residual detected E2 6/22/2000 4302 9 W LSD in the water distribution system. Bellevue Bellevue Big Pond Water distribution system is D1 6/8/2011 299 148 E LSD undergoing maintenance or repairs. Bellevue Beach Bellevue Beach Unnamed Brook No free chlorine residual detected E2 9/18/1997 5310 80 E LSD in the water distribution system. Benoit's Siding Benoit's Siding (aka Drilled Disinfection system is off, due to C1 7/9/2010 633 0 W LSD Bennett's Siding) maintenance or mechanical failure. Benoit's Siding Doyles # 2 Well Doyles Disinfection system is off, due to C1 7/9/2010 633 15 W LSD maintenance or mechanical failure. Benton Benton Little Pond No free chlorine residual detected E2 3/20/2012 13 167 C LSD in the water distribution system. Bird Cove Bird Cove (+Brig Inner Gilmour Pond No free chlorine residual detected E2 8/2/2011 244 137 W MUN Bay) in the water distribution system. BOIL WATER ADVISORIES & HEALTH RISK IN NL 112
Biscay Bay Biscay Bay Unnamed Pond Water Supply has no disinfection A 6/23/2000 4301 38 E LSD system. Black Duck Black Duck (Siding) #1 Well Water Supply has no disinfection A 6/21/2000 4303 25 W LSD system. Black Duck Black Duck (Siding) #2 Well Chlorination system is turned off B1 6/22/2000 4302 29 W LSD by operator, due to taste. Black Duck Cove Black Duck Cove Long Pond - Black Chlorination system is turned off B3 12/17/1997 5220 125 W LSD Duck Cove Intake by operator, due to lack of funds to operate. Black Tickle-Domino Black Tickle- Martin's Pond - Tap None Listed Z 1/11/2011 447 0 L LSD Domino - Outside at Pumphouse Tap Branch Branch Valley Pond Water Supply has no disinfection A 1/1/1989 8492 72 E MUN system. Brent's Cove Brent's Cove Paddy's Pond No free chlorine residual detected E2 2/20/1991 7712 204 W MUN in the water distribution system. Brig Bay Brig Bay Inner Gilmour Pond No free chlorine residual detected E2 8/2/2011 244 40 W LSD in the water distribution system. Brigus South Dunphey's Hill area #2 Well Dunphey's Chlorination system is turned off B1 5/30/2003 3230 30 E LSD Hilll by operator, due to taste. Brigus South Forge Hill area #1 Well Forge Hill Chlorination system is turned off B1 5/30/2003 3230 25 E LSD by operator, due to taste. Brigus South Near highway #3 Well Main Road Chlorination system is turned off B1 5/30/2003 3230 26 E LSD by operator, due to taste. Britannia Britannia No free chlorine residual detected E2 8/2/2010 609 E UNC in the water distribution system. Bryant's Cove Bryant's Cove South #1 Well - Bert Water distribution system is D1 6/18/2007 1750 279 E MUN Side James Well undergoing maintenance or #2 Well - Baxter repairs. Bowering Well
Buchans Junction Buchans Junction Lapland Pond Total coliforms detected and F3 8/12/2011 234 96 C LSD confirmed in repeat sample. Bunyan's Cove Bunyan's Cove #2 Wellfield Inadequately treated water was D3 5/23/2006 2141 39 E LSD introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Burgeo Burgeo Long Pond Water entering distribution system E1 5/7/2010 696 1607 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Burgeo Burgeo Long Pond Partial. No free chlorine residual E2 8/14/2001 3884 1607 W MUN detected in the water distribution system. Burlington Burlington Eastern Island Pond Water distribution system is D1 12/24/2010 465 376 W MUN undergoing maintenance or repairs. Calvert Calvert Water Supply has no disinfection A 6/23/2000 4301 29 E LSD system. BOIL WATER ADVISORIES & HEALTH RISK IN NL 113
Campbellton Campbellton Indian Arm Brook Disinfection system is off, due to C2 2/27/2012 35 474 C MUN lack of chlorine or other disinfectant. Cape Freels North Cape Freels North Long Pond Partial. Disinfection system is C1 3/14/2008 1480 145 C LSD off, due to maintenance or mechanical failure. Cartwright Cartwright Burdett's Pond Inadequately treated water was D3 5/23/2006 2141 552 L MUN introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Castor River North Castor River North Long Pond (same as Water entering distribution system E1 1/1/1991 7762 172 W LSD Bartletts Harbour) or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Castor River South Castor River South Unnamed Water Supply has no disinfection A 1/1/1991 7762 169 W LSD system. Cavendish North Side #1 Well - Max No free chlorine residual detected E2 5/9/2001 3981 32 E LSD Cavendish Bishop in the water distribution system. Cavendish North Side #2 Well - Tom Disinfection system is off, due to C1 6/10/2003 3219 25 E LSD Cavendish Critch maintenance or mechanical failure. Chanceport Chanceport Bridger's Cove No free chlorine residual detected E2 8/11/1989 8270 35 C LSD Pond in the water distribution system. Charlottetown Charlottetown Middle Pond Water distribution system is D1 11/25/2011 129 168 L MUN (Labrador) (Labrador) undergoing maintenance or repairs. Charlottetown Charlottetown rec Rec Centre Well Water Supply has no disinfection A 6/9/2009 1028 4 L MUN (Labrador) centre system. Churchill Falls Churchill Falls Smallwood Partial. Water Supply has no A 10/14/2008 1266 634 L UNC Reservoir disinfection system. Churchill Falls Churchill Falls Smallwood Partial. Disinfection system is off, C1 6/8/2010 664 634 L UNC Reservoir due to maintenance or mechanical failure. Churchill Falls Churchill Falls Smallwood Partial. Disinfection system is C1 10/30/2008 1250 634 L UNC Reservoir off, due to maintenance or mechanical failure. Clarke's Beach Otterbury #1 Well - Quinlon Water Supply has no disinfection A 6/23/2000 4301 19 E MUN Well system. Clarke's Beach Otterbury #2 Well - Delaney Water Supply has no disinfection A 6/23/2000 4301 24 E MUN Well system. Conche Conche Martin's Brook Water entering distribution system E1 5/18/2001 3972 225 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Conne River Conne River Southwest Brook Disinfection system is off, due to C1 12/13/2011 111 837 C UNC maintenance or mechanical failure. BOIL WATER ADVISORIES & HEALTH RISK IN NL 114
Corner Brook Corner Brook (All of Trout Pond, Third Partial. Water distribution system D1 11/9/2011 145 15077 W MUN eastside, portion of Pond (2 intakes) is undergoing maintenance or westside) (+Massey repairs. Drive)
Cottrell's Cove Cottrell's Cove Cotrell's Pond Total coliforms detected and F3 8/27/2009 949 151 C LSD confirmed in repeat sample. Cox's Cove Cox's Cove Cox's Brook Escherichia coli (E. coli) detected F2E 12/16/2011 108 646 W MUN AND repeat samples can not be taken as required. Cox's Cove Upper Area Upper Area Water distribution system is D1 3/15/2011 384 60 W MUN Wellfield undergoing maintenance or repairs. Crow Head Crow Head Oars Pond Disinfection system is off, due to C1 9/4/2008 1306 205 C MUN maintenance or mechanical failure. Deep Bight Deep Bight Deep Bight Well Inadequately treated water was D3 4/14/2006 2180 164 E LSD Field introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Dildo Hill Road Area #2 Well Disinfection system is off, due to C1 6/23/2000 4301 91 E LSD maintenance or mechanical failure. Eddies Cove West Eddies Cove West Unnamed Water Supply has no disinfection A 4/9/2003 3281 72 W LSD system. Elliston Elliston Big Pond Inadequately treated water was D3 3/14/2012 19 306 E MUN introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Flat Bay Flat Bay (East) #1 Well Chlorination system is turned off B4 3/5/2010 759 78 W LSD by operator, due to Non- consumption Order. Flat Bay West Birchy Brook - #1 Well Water Supply has no disinfection A 6/21/2000 4303 32 W UNC Federation of Indians system. Forresters Point Forresters Point Rudges Pond No free chlorine residual detected E2 11/29/1995 5969 197 W LSD in the water distribution system. Francois Francois Our Pond Water Supply has no disinfection A 4/9/1997 5472 130 C LSD system. Freshwater Freshwater #2 Well - Covage's Disinfection system is off, due to C1 6/23/2000 4301 23 E LSD (Carbonear) Lane Well maintenance or mechanical failure. Freshwater Freshwater #3 Well - Wallace Disinfection system is off, due to C1 6/23/2000 4301 44 E LSD (Carbonear) Snow Well maintenance or mechanical failure. Gallants Gallants Gallant's Brook Water Supply has no disinfection A 5/1/1997 5450 54 W MUN system. Gander Bay South George's Point, Barry's Brook Disinfection system is off, due to C1 10/12/2010 538 315 C LSD Harris Point maintenance or mechanical failure. BOIL WATER ADVISORIES & HEALTH RISK IN NL 115
Gaskiers Gaskiers-Point La Big Hare Hill Pond Water entering distribution system E1 12/22/2008 1197 290 E MUN Haye or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Gaultois Gaultois Piccaire Pond Disinfection system is off, due to C1 10/16/2001 3821 147 C MUN maintenance or mechanical failure. George's Brook- George's Brook George's Brook Escherichia coli (E. coli) detected F5 3/14/2012 19 321 E LSD Milton and confirmed in repeat sample. George's Brook- Milton Lilly Pond Total coliforms detected and F3 7/29/2011 248 348 E LSD Milton confirmed in repeat sample. Goose Cove East Goose Cove East Jack's Pond No free chlorine residual detected E2 8/31/1999 4598 234 W MUN in the water distribution system. Grand Le Pierre Grand Le Pierre Nip Nose Pond No free chlorine residual detected E2 10/10/1997 5288 264 E MUN in the water distribution system. Grates Cove Grates Cove Centre #1 Cyril Meadus Disinfection system is off, due to C1 6/23/2000 4301 98 E LSD Well maintenance or mechanical failure. Grates Cove Grates Cove South #4 Stoyles Hill Well Disinfection system is off, due to C1 6/23/2000 4301 50 E LSD End maintenance or mechanical failure. Great Brehat Great Brehat Little Steady Pond No free chlorine residual detected E2 12/17/1997 5220 103 W LSD in the water distribution system. Great Codroy Great Codroy East #1 Well No free chlorine residual detected E2 6/21/2000 4303 67 W LSD in the water distribution system. Great Codroy Great Codroy West #2 Well No free chlorine residual detected E2 6/22/2000 4302 22 W LSD in the water distribution system. Green Island Brook Green Island Brook Green Island Brook No free chlorine residual detected E2 9/11/2007 1665 193 W LSD in the water distribution system. Green Island Brook Green Island Brook Green Island Brook No free chlorine residual detected E2 9/11/2007 1665 193 W LSD in the water distribution system. Green's Harbour Green's Harbour Water Supply has no disinfection A 3/14/2001 4037 0 E LSD West system. Greenspond Greenspond Shambler's Cove Total coliforms detected and F3 1/13/2012 80 365 C MUN Pond confirmed in repeat sample. Grey River Grey River Big Charlie's Pond Water Supply has no disinfection A 2/20/1997 5520 125 C LSD system. Harbour Grace Riverhead Mercer's Rd. Well Escherichia coli (E. coli) detected F2E 8/4/2011 242 43 E MUN AND repeat samples can not be taken as required. Harbour Mille-Little Harbour Mille, Little Head Pond Water Supply has no disinfection A 11/20/2003 3056 176 E LSD Harbour East Harbour East system. (Fortune Bay)
Harbour Mille-Little Harbour Mille, Little Head Pond Total coliforms detected and F3 11/20/2003 3056 176 E LSD Harbour East Harbour East confirmed in repeat sample. (Fortune Bay) BOIL WATER ADVISORIES & HEALTH RISK IN NL 116
Harcourt-Monroe- Harcourt-Monroe- Developed Spring Water entering distribution system E1 6/12/2003 3217 40 E LSD Waterville Waterville or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Heart's Desire Heart's Desire Terrence Pond Water distribution system is D1 8/11/2010 600 226 E MUN undergoing maintenance or repairs. Hopeall Hopeall Charles Cumby Water Supply has no disinfection A 3/14/2001 4037 19 E LSD Well system. Hopeall Gilberts Hill Gilberts Hill Well Water Supply has no disinfection A 3/14/2001 4037 30 E LSD system. Hopedale Hopedale American Pond Inadequately treated water was D3 2/15/2012 47 530 L MUN introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Howley Howley Sandy Lake Water entering distribution system E1 11/1/2002 3440 241 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Howley Howley Sandy Lake Total coliform or Escherichia (E. F2 11/1/2002 3440 241 W MUN coli) detected AND repeat samples can not be taken as required. Howley Howley Sandy Lake Escherichia coli (E. coli) detected F5 11/1/2002 3440 241 W MUN and confirmed in repeat sample. Indian Bay Indian Bay Indian Bay Brook Total coliforms detected and F3 9/26/2008 1284 196 C MUN confirmed in repeat sample. Jackson's Arm Jackson's Arm Unnamed Brook Escherichia coli (E. coli) detected F2E 3/30/2012 3 374 W MUN AND repeat samples can not be taken as required. Jackson's Cove- Silverdale, Nickey's Nickey's Nose Cove Chlorination system is turned off B3 12/24/2010 465 57 C LSD Langdon's Cove- Nose Cove Pond by operator, due to lack of funds Silverdale to operate.
Jackson's Cove- Langdon's Cove #3 Well Langdon's Chlorination system is turned off B2 4/13/2008 1450 37 C LSD Langdon's Cove- Cove Well by operator, due to perceived Silverdale health risks.
Jean de Baie Jean de Baie Colleen's Pond Chlorination system is turned off B2 1/1/1996 5936 178 E LSD (Back Up Supply) by operator, due to perceived health risks. Jean de Baie Jean de Baie #1 Well Chlorination system is turned off B3 1/1/1996 5936 205 E LSD by operator, due to lack of funds to operate. L'Anse au Clair L'Anse au Clair Park Pond None Listed Z 1/7/2010 816 226 L MUN L'Anse au Loup L'Anse au Loup L'anse Au Loup Disinfection system is off, due to C1 5/28/2005 2501 234 L MUN River maintenance or mechanical failure. La Poile La Poile Black Duck Pond Chlorination system is turned off B1 1/1/1995 6301 111 W LSD by operator, due to taste. BOIL WATER ADVISORIES & HEALTH RISK IN NL 117
LaScie La Scie Stakes Pond Water Supply has no disinfection A 2/20/1991 7712 955 W MUN system. Lamaline Lamaline Upper Hodges Pond Water distribution system is D1 10/24/2011 161 79 E MUN undergoing maintenance or repairs. Lance Cove Lance Cove Local Service Chlorination system is turned off B1 8/5/2003 3163 18 E LSD District Well by operator, due to taste. Lance Cove Lance Cove Local Service Disinfection system is off, due to C2 8/5/2003 3163 18 E LSD District Well lack of chlorine or other disinfectant. Lawn Lawn Brazil Pond Partial. No free chlorine residual E2 1/12/2012 81 705 E MUN detected in the water distribution system.
Little Bay Little Bay Mine Pond Total coliforms detected AND F2T 8/4/2011 242 25 C MUN repeat samples can not be taken as required. Little Bay Little Bay First Pond Inadequately treated water was D3 12/9/2011 115 110 C MUN introduced into the system due to fire flows, flushing operations, minor power outage or other pressure loss. Little Harbour East Little Harbour East Unnamed Pond No free chlorine residual detected E2 1/1/1996 5936 118 E LSD (Placentia Bay) in the water distribution system. Little St. Lawrence Little St. Lawrence Butler's Brook (2 Chlorination system is turned off B3 5/23/1999 4698 122 E LSD Intakes) by operator, due to lack of funds to operate. Long Harbour-Mount Long Harbour-Mount Shingle Pond and/or Disinfection system is off, due to C1 10/7/2011 178 211 E MUN Arlington Heights Arlington Heights Trout Pond (2 maintenance or mechanical Intakes) failure.
Loon Bay Loon Bay Southeast Pond Total coliforms detected and F3 3/14/2012 19 155 C LSD confirmed in repeat sample. Lower Lance Cove Lower Lance Cove Big Long Pond No free chlorine residual detected E2 8/2/2010 609 133 E LSD in the water distribution system. Main Brook Main Brook Joe Burt's Pond Disinfection system is off, due to C1 7/4/2011 273 293 W MUN maintenance or mechanical failure. Mainland Mainland Caribou Brook Escherichia coli (E. coli) detected F5 9/29/2010 551 311 W LSD and confirmed in repeat sample. Marysvale Marysvale, Long Drilled Water entering distribution system E1 2/1/2008 1522 419 E LSD Pond or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Mattis Point Mattis Point Drilled Disinfection system is off, due to C1 4/10/2003 3280 136 W LSD maintenance or mechanical failure. Middle Arm Middle Arm Dam Pond Brook Disinfection system is off, due to C1 9/15/2008 1295 517 W MUN maintenance or mechanical failure. BOIL WATER ADVISORIES & HEALTH RISK IN NL 118
Miles Cove Miles Cove Paddock's Pond Escherichia coli (E. coli) detected F4 9/29/2011 186 140 C MUN in an initial sample(s) is considered extensive and the water system has other known problems. Morrisville Morrisville Morrisville Pond Water entering distribution system E1 8/21/2006 2051 128 C MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Newman's Cove Newman's Cove Heale Pond Brook Water entering distribution system E1 3/26/2008 1468 192 E LSD or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Nippers Harbour Nippers Harbour Blackhead Pond No free chlorine residual detected E2 11/25/1996 5607 150 W MUN Brook in the water distribution system. Norman's Cove-Long Norman's Cove-Long John Newhooks Partial. Water distribution system D1 2/2/2012 60 773 E MUN Cove Cove Pond is undergoing maintenance or repairs. North Harbour North Harbour Grandfather's Pond No free chlorine residual detected E2 1/1/1996 5936 152 E LSD in the water distribution system. North Harbour North Harbour North Communal Well Water Supply has no disinfection A 6/15/2000 4309 6 E LSD End, tap outlet system. Pacquet Pacquet Big Brook Water entering distribution system E1 2/20/1991 7712 200 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Parkers Cove Parkers Cove Unnamed brook Water entering distribution system E1 12/15/2010 474 214 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Petit Forte Petit Forte Reddy's Pond Disinfection system is off, due to C1 1/1/1996 5936 97 E LSD maintenance or mechanical failure. Phillips Head Phillips Head Dogberry Brook Total coliforms detected and F3 7/28/2006 2075 142 C LSD confirmed in repeat sample. Piccadilly Head Piccadilly Head Unnamed Brook Chlorination system is turned off B3 9/28/2010 552 154 W LSD (+West Bay) by operator, due to lack of funds to operate. Piccadilly Slant- Abraham's Cove #2 Well - Chlorination system is turned off B3 9/28/2010 552 414 W LSD Abraham's Cove Abraham's Cove by operator, due to lack of funds to operate. Piccadilly Slant- Piccadilly Slant #1 Well - Piccadilly Chlorination system is turned off B3 9/28/2010 552 364 W LSD Abraham's Cove Slant by operator, due to lack of funds to operate. Pidgeon Cove-St. Pigeon Cove Long Pond (Intake No free chlorine residual detected E2 8/25/1994 6430 81 W LSD Barbe #1) in the water distribution system. Plum Point Plum Point Grand Pond No free chlorine residual detected E2 12/17/1997 5220 145 W LSD BOIL WATER ADVISORIES & HEALTH RISK IN NL 119
in the water distribution system. Point Lance Point Lance Unnamed Pond Water Supply has no disinfection A 1/1/1989 8492 119 E MUN system. Point May Point May Short's Pond Water entering distribution system E1 4/26/2010 707 260 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Pollards Point Pollards Point, Country Cove Pond Water Supply has no disinfection A 1/1/1987 9223 354 W LSD Country Cove system. Pollards Point Pollards Point East George Ricks Pond Water Supply has no disinfection A 1/1/1987 9223 W LSD system. Pool's Cove Pool's Cove Widgeon Pond Water entering distribution system E1 9/9/1998 4954 189 C MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Port Anson Port Anson Anchor Pond Water entering distribution system E1 8/21/2006 2051 155 C MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Port Hope Simpson Port Hope Simpson Arnold's Brook and Water distribution system is D1 8/6/2010 605 509 L MUN Pond undergoing maintenance or repairs. Port Kirwan North Side Dug Well / Drilled Water entering distribution system E1 6/23/2000 4301 37 E MUN Well or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Port Kirwan North Side Dug Well / Drilled Total coliforms detected and F3 6/23/2000 4301 37 E MUN Well confirmed in repeat sample. Port Rexton Port Rexton #1 Well - Lois Long Water Supply has no disinfection A 9/21/2001 3846 7 E MUN Well system. Port Rexton Port Rexton #2 Well - Edmund Water Supply has no disinfection A 9/21/2001 3846 18 E MUN (Seasonal Use) Brown's Well system. Port Rexton Hunchback Hill #3 Well - Harold Water Supply has no disinfection A 9/21/2001 3846 21 E MUN Vivian's Well system. Port Rexton Ship Cove #5 Well - Mabel Water Supply has no disinfection A 9/21/2001 3846 18 E MUN Clarke's Well system. Port Rexton Ship Cove #6 Well - Banister's Water Supply has no disinfection A 9/21/2001 3846 3 E MUN Well system. Port Rexton Champneys Arm Champney's Arm Water Supply has no disinfection A 9/21/2001 3846 27 E MUN Well system. Portugal Cove South Portugal Cove South Wrights Brook Water entering distribution system E1 1/1/1984 10319 222 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least BOIL WATER ADVISORIES & HEALTH RISK IN NL 120
0.3 mg/l or equivalent CT value.
Portugal Cove South Portugal Cove South Wrights Brook Total coliforms detected and F3 1/1/1984 10319 222 E MUN confirmed in repeat sample. Pynn's Brook Pynn's Brook Pynn's Brook Total coliform or Escherichia (E. F2 8/20/2009 956 64 W LSD coli) detected AND repeat samples can not be taken as required. Red Bay Red Bay Northern Brook No free chlorine residual detected E2 9/1/1994 6423 227 L MUN in the water distribution system. Reidville Reidville Humber Canal, Water distribution system is D1 1/3/2012 90 480 W MUN Grand Lake undergoing maintenance or repairs. Riverhead Riverhead (St. Well Field Disinfection system is off, due to C1 12/22/2011 102 220 E MUN Mary's Bay) maintenance or mechanical failure. Rushoon Rushoon Big Pond Brook Water entering distribution system E1 3/28/2000 4388 319 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Seal Cove (FB) Seal Cove, F.B. Big Black Duck Water Supply has no disinfection A 8/17/2005 2420 315 C MUN Pond system. Sheaves Cove Sheaves Cove Unnamed Brook Disinfection system is off, due to C1 9/8/2008 1302 66 W LSD maintenance or mechanical failure. Sheaves Cove Sheaves Cove Drilled Water entering distribution system E1 9/8/2011 207 59 W LSD or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Ship Cove-Lower Ship Cove, Jerry's #5 Well - Murdock No free chlorine residual detected E2 6/21/2000 4303 34 W LSD Cove-Jerry's Nose Nose Wheeler Well in the water distribution system. Ship Cove-Lower Lower Cove #6 Well - Lower No free chlorine residual detected E2 6/21/2000 4303 W LSD Cove-Jerry's Nose Cove Well in the water distribution system. Ship Cove-Lower Ship Cove East #3 Well - Bernard No free chlorine residual detected E2 6/21/2002 3573 W LSD Cove-Jerry's Nose Brake Well in the water distribution system. Ship Cove-Lower Ship Cove, Jerry's #2 Well - Howard No free chlorine residual detected E2 6/21/2002 3573 W LSD Cove-Jerry's Nose Nose & Rodney Jesso in the water distribution system. Well Ship Cove-Lower Ship Cove, Jerry's #4 Well - Nancy Escherichia coli (E. coli) detected F5 7/25/2011 252 W LSD Cove-Jerry's Nose Nose Rowe Well and confirmed in repeat sample. Ship Cove-Lower Ship Cove, Jerry's #1 Well - PJ's No free chlorine residual detected E2 6/21/2002 3573 W LSD Cove-Jerry's Nose Nose Variety Well in the water distribution system. Shoe Cove Shoe Cove Second Pond Chlorination system is turned off B3 5/25/2005 2504 198 W LSD by operator, due to lack of funds to operate. BOIL WATER ADVISORIES & HEALTH RISK IN NL 121
Small Point-Adam's Adam's Cove #1 Well - Reg Disinfection system is off, due to C1 6/23/2000 4301 73 E MUN Cove-Blackhead- Bursey Well maintenance or mechanical Broad Cove failure. Small Point-Adam's Blackhead #4 Well - Leonard Disinfection system is off, due to C1 6/23/2000 4301 182 E MUN Cove-Blackhead- King Well maintenance or mechanical Broad Cove failure. Small Point-Adam's Broad Cove #6 Well - Herb Disinfection system is off, due to C1 6/23/2000 4301 32 E MUN Cove-Blackhead- Trickett Well maintenance or mechanical Broad Cove failure. Small Point-Adam's Broad Cove #7 Well - Gin Disinfection system is off, due to C1 6/23/2000 4301 53 E MUN Cove-Blackhead- Badcock Well maintenance or mechanical Broad Cove failure. Small Point-Adam's Small Point #8 Well - Effie Disinfection system is off, due to C1 6/23/2000 4301 64 E MUN Cove-Blackhead- Flight Wells maintenance or mechanical Broad Cove failure. Small Point-Adam's Small Point #9 Well - Walter Disinfection system is off, due to C1 6/23/2000 4301 85 E MUN Cove-Blackhead- Reynolds Well maintenance or mechanical Broad Cove failure. Snook's Arm Snook's Arm NFLD Hydro Water Supply has no disinfection A 2/20/1991 7712 10 W LSD Penstock system. Sop's Arm Sop's Arm Little Tickle Pond No free chlorine residual detected E2 1/1/1990 8127 224 W LSD in the water distribution system. South Dildo South Dildo #5 Well - Calvin Disinfection system is off, due to C1 4/23/2003 3267 49 E LSD Reid Well maintenance or mechanical failure. Southern Harbour Southern Harbour Brigades Pond Water entering distribution system E1 1/31/2011 427 474 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. St. Andrews St. Andrew's #1 Well Disinfection system is off, due to C1 7/9/2010 633 66 W LSD maintenance or mechanical failure. St. Andrews St. Andrew's #2 Well Disinfection system is off, due to C1 7/9/2010 633 98 W LSD maintenance or mechanical failure. St. Andrews St. Andrew's East #3 Well Disinfection system is off, due to C1 7/9/2010 633 33 W LSD maintenance or mechanical failure. St. Andrews Air Strip Road #4 Well Strip Road Disinfection system is off, due to C1 7/9/2010 633 7 W LSD Well maintenance or mechanical failure. St. Anthony Bight St. Anthony Bight Cabbox Pond No free chlorine residual detected E2 10/22/1997 5276 147 W LSD in the water distribution system. St. Bernard's-Jacques St. Bernard's-Jacques Rattle Brook No free chlorine residual detected E2 10/10/2006 2001 525 E MUN Fontaine Fontaine in the water distribution system. St. Bride's St. Bride's North Side Brook Water Supply has no disinfection A 1/1/1989 8492 386 E MUN system. St. Bride's St. Bride's South Side Brook Disinfection system is off, due to C1 1/1/1989 8492 E MUN maintenance or mechanical failure. BOIL WATER ADVISORIES & HEALTH RISK IN NL 122
St. Joseph's St. Joseph's S.M.B. Drilled Water Supply has no disinfection A 6/23/2000 4301 54 E MUN system. St. Judes St. Judes Uncle Arthur Brook Chlorination system is turned off B3 1/24/2005 2625 35 W LSD by operator, due to lack of funds to operate. St. Judes St. Judes Chute Brook No free chlorine residual detected E2 12/16/2011 108 24 W LSD in the water distribution system. St. Lunaire-Griquet St. Lunaire-Griquet Joe's Pond Water entering distribution system E1 8/1/2011 245 666 W MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. St. Mary's St. Mary's Wellfield Water entering distribution system E1 7/31/2008 1341 450 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. St. Patricks St. Patricks David Joy Well Water Supply has no disinfection A 2/20/1991 7712 37 C LSD system. Steady Brook Steady Brook Steady Brook No free chlorine residual detected E2 3/16/2012 17 394 W MUN in the water distribution system. Straitsview Straitsview Saddle Hill Pond No free chlorine residual detected E2 6/17/1998 5038 105 W LSD in the water distribution system. Swift Current Swift Current Drilled Water Supply has no disinfection A 4/30/1999 4721 21 E LSD system. Swift Current Swift Current Black Duck Pond Water Supply has no disinfection A 4/30/1999 4721 E LSD system. Thornlea Thornlea Big Bakeapple Pond No free chlorine residual detected E2 12/16/2011 108 119 E LSD in the water distribution system. Tilt Cove Tilt Cove Castle Rock Pond Water Supply has no disinfection A 2/20/1991 7712 7 W MUN system. Tompkins Tompkins Greg Wall Well Disinfection system is off, due to C1 7/9/2010 633 87 W LSD maintenance or mechanical failure. Trepassey Trepassey Miller's Pond Water entering distribution system E1 6/23/2000 4301 763 E MUN or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Trepassey Trepassey Miller's Pond Total coliforms detected and F3 6/23/2000 4301 763 E MUN confirmed in repeat sample. Upper Ferry Upper Ferry - Lower #1 Well - Gerard Water entering distribution system E1 3/21/2006 2204 49 W LSD Brownrigg Well or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Upper Ferry Upper Ferry - Middle #2 Well - Hughie No free chlorine residual detected E2 7/8/2003 3191 52 W LSD MacIssac Well in the water distribution system. Upper Ferry Upper Ferry - Upper #3 Well - Marshall No free chlorine residual detected E2 9/19/2006 2022 41 W LSD Devoe Well in the water distribution system. BOIL WATER ADVISORIES & HEALTH RISK IN NL 123
Upper Ferry Upper Ferry #4 Well - Angus No free chlorine residual detected E2 7/13/2003 3186 22 W LSD MacNeil Well in the water distribution system. Wabana Wabana Middleton Ave Water Supply has no disinfection A 6/23/2000 4301 E MUN system. Wabana Wabana #3 Yard West Water Supply has no disinfection A 6/23/2000 4301 224 E MUN Mines Road system. Wabana Wabana #4-West Mines Water Supply has no disinfection A 6/23/2000 4301 271 E MUN Road system. Wabana Wabana Normore Crescent Water Supply has no disinfection A 6/23/2000 4301 223 E MUN East #1 system. Wabana Wabana Quigley's Line Water Supply has no disinfection A 6/23/2000 4301 223 E MUN system. Wabana Wabana Scotia #1 Water Supply has no disinfection A 6/23/2000 4301 223 E MUN system. Wabana Wabana St. Edward's Water Supply has no disinfection A 6/23/2000 4301 60 E MUN Memorial St. system. West Bay West Bay Unnamed Brook Chlorination system is turned off B3 9/28/2010 552 W LSD by operator, due to lack of funds to operate. West St. Modeste West St. Modeste Well Field Total coliforms detected AND F2T 11/8/2010 511 140 L MUN repeat samples can not be taken as required. Westport Westport Western Brook Water entering distribution system E1 2/20/1991 7712 227 W MUN Pond or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. Wild Cove Wild Cove Hedderson's Pond Water entering distribution system E1 2/20/1991 7712 88 W LSD Brook or facility, after a minimum 20 minute contact time does not have a free chlorine residual of at least 0.3 mg/l or equivalent CT value. William's Harbour William's Harbour Beaver Pond Chlorination system is turned off B1 7/7/2000 4287 52 L LSD by operator, due to taste. Winterton Winterton Western Pond Water distribution system is D1 3/20/2012 13 518 E MUN undergoing maintenance or repairs. Woodstock Woodstock Mill Pond No free chlorine residual detected E2 7/26/2007 1712 199 W MUN in the water distribution system. BOIL WATER ADVISORIES & HEALTH RISK IN NL 124
Appendix B: Raw source water quality data for microbiologic parameters
BOIL WATER ADVISORIES & HEALTH RISK IN NL 125
Table B1: Tap water bacteriological data for 10 out of 12 representative communities on BWAs
Total Coliforms E.Coli Town Date (CFU/100 mL) (CFU/100 mL) Bay de Verde 2006/Aug/21 1 1 Bird Cove 5/3/2010 20 4 Bird Cove 5/3/2010 15 4 Bird Cove 2007/Oct/30 80 3 Bird Cove 2007/Oct/30 37 4 Bird Cove 2007/May/23 45 3 Bird Cove 2007/May/23 39 5 Bird Cove 2007/May/23 51 12
Bird Cove 2007/Aug/23 80 30
Bird Cove 2007/Aug/23 59 24 Bird Cove 2007/Aug/23 80 32 Bird Cove 2006/Dec/01 58 13 Bird Cove 2006/Dec/01 80 12 Bird Cove 2006/Dec/01 60 14 Bird Cove 2006/Dec/01 70 27
Bird Cove 2003/May/26 4 1 Campbellton 2004/Nov/17 80 13 Campbellton 2004/Nov/17 26 3 Cartwright 8/27/2008 60 12
Cartwright 8/12/2009 16 4 Cartwright 7/29/2009 50 1 Cartwright 2005/Aug/02 35 1 Cartwright 2004/Jul/05 2 1 Cartwright 2004/Jul/28 47 3 Cartwright 2003/Sep/03 80 1 Cartwright 2002/Oct/07 35 5 Little Bay 2/22/2010 21 3 Little Bay 2/22/2010 19 3 Little Bay 2007/Jul/24 1 1 Little Bay 2008/Mar/25 3 1 Little Bay 2004/Sep/27 37 2 Mainland 11/24/2010 80 1 Mainland 2006/Jul/24 33 33 Mainland 2005/Jul/12 9 5 BOIL WATER ADVISORIES & HEALTH RISK IN NL 126
Mainland 2005/Jan/26 1 1 Mainland 2003/Oct/07 80 5 Mainland 2003/Aug/11 80 60 Mainland 2003/Aug/11 80 60 Mainland 2003/Oct/07 80 12 Miles Cove 8/11/2010 80 1 Miles Cove 2006/Jul/26 80 4 Miles Cove 2006/Jul/26 80 12 Trepassey 2002/Jul/24 1 1 Piccadilly Head 2002/Jul/23 40 1 Piccadilly Head 2002/Oct/16 1 1 Piccadilly Head 2003/Aug/11 64 14 Piccadilly Head 2003/Oct/07 21 21 Piccadilly Head 2003/Dec/10 60 3 Piccadilly Head 2003/Jul/21 31 30 Piccadilly Head 2003/Aug/11 11 1 Piccadilly Head 2004/Jan/12 10 5 Churchill Falls 2004/Nov/08 19 1 Churchill Falls 2004/Aug/16 18 2 Churchill Falls 2004/May/19 22 9 Churchill Falls 2004/Aug/25 17 1 Churchill Falls 2005/Oct/17 13 2 Churchill Falls 2005/Aug/10 20 1 Churchill Falls 2006/Aug/14 13 2 Churchill Falls 2006/May/15 4 1 Churchill Falls 2007/Aug/29 4 3 Churchill Falls 2007/Jun/11 1 1
BOIL WATER ADVISORIES & HEALTH RISK IN NL 127
Table B2: Pathogenic source water quality data for St. John’s, Bay Bulls Big Pond supply
E. coli / 100 mL Bay Bulls Big Pond Raw Water 2007 2008 2009 2010 2011 Jan 3 2 2 3 15 Jan 1 1 1 3 17 Jan 4 1 2 3 Jan 2 2 4 Jan 2 1 3 Jan 1 4 Jan 2 Jan Jan Feb 1 1 Feb 1 Feb 1 Feb 1 Feb Feb Mar 1 1 1 Mar 1 1 Mar 1 2 Mar 1 Mar 1 Mar 1 Mar Mar Apr 2 1 9 1 Apr 10 5 2 Apr 57 10 Apr 16 5 Apr 11 Apr 15 Apr May 1 5 5 5 5 May 2 2 2 30 5 May 19 4 4 10 8 May 3 10 2 4 2 May 8 8 1 10 3 May 1 3 2 4 3 May 3 1 3 May 10 2 June 1 1 1 3 8 June 1 2 5 2 5 June 1 1 2 21 10 June 20 10 3 June 1 8 5 BOIL WATER ADVISORIES & HEALTH RISK IN NL 128
June 4 16 2 June 9 1 June 4 3 July 3 1 10 1 10 July 1 1 10 2 11 July 1 10 2 1 1 July 20 20 1 July 11 1 July 18 July 9 July 20 July 8 August 46 1 3 9 21 August 1 2 7 1 6 August 1 20 1 10 3 August 7 3 2 2 5 August 1 3 2 4 3 August 50 20 4 10 August 14 1 2 August 10 6 August 10 August 13 August 4 August 60 August 80 September 10 1 12 6 1 September 10 4 12 2 1 September 10 20 7 1 7 September 100 100 10 17 20 September 30 80 60 140 3 September 18 100 100 5 September 12 19 36 2 September 5 12 19 2 October 20 10 7 11 1 October 3 20 100 6 18 October 10 50 50 6 8 October 8 110 80 1 4 October 10 40 20 5 12 October 5 30 20 5 3 October 10 2 2 October 20 16 October 4 2 8 100 November 10 10 10 6 200 November 10 14 5 3 10 November 30 2 7 14 November 2 2 1 30 November 10 1 3 10 November 23 10 3 8 BOIL WATER ADVISORIES & HEALTH RISK IN NL 129
November 2 1 November November December 12 20 2 1 5 December 10 50 5 3 4 December 5 27 2 10 2 December 3 40 2 1 3 December 1 25 1 6 December 20 21 10 December 9 40 December 4
Giardia Crypto Date (cysts/100 L) (oocysts/100 L) 11-Oct-06 0 0 24-Nov-08 0 0
BOIL WATER ADVISORIES & HEALTH RISK IN NL 130
Table B3: Pathogenic source water quality data for St. John’s, Windsor Lake supply
E. coli / 100 mL Windsor Lake Raw Water 2007 2008 2009 2010 2011 Jan 18 1 18 10 11 Jan 32 2 6 1 110 Jan 170 1 6 2 40 Jan 100 2 2 35 Jan 35 4 28 Jan 24 2 26 Jan 10 12 Jan 9 20 Jan 10 Feb 1 10 10 9 Feb 2 10 Feb 2 2 Feb 2 1 Feb 2 1 Feb 1 1 Mar 1 1 2 10 Mar 1 3 3 Mar 2 1 Mar 3 Mar 2 Mar 1 Mar 1 Mar 1 Apr 1 1 3 3 Apr 1 4 1 1 Apr 2 4 15 6 Apr 4 17 3 Apr 3 7 2 Apr 1 10 2 Apr 3 3 May 14 11 8 4 1 May 4 3 5 3 1 May 3 6 10 4 2 May 7 15 3 May 1 3 May 4 May May June 1 2 2 1 1 June 3 4 1 2 10 June 1 4 4 1 6 June 2 1 1 16 2 June 4 1 5 2 BOIL WATER ADVISORIES & HEALTH RISK IN NL 131
June 4 1 June 6 June July 1 3 10 1 2 July 1 4 4 4 3 July 1 3 8 1 1 July 2 8 1 2 July 6 6 4 July 1 5 10 July 7 July July August 1 3 6 1 2 August 1 3 9 5 11 August 5 10 14 2 2 August 2 20 60 2 12 August 430 20 5 7 10 August 30 130 4 7 August 80 17 4 30 August 26 8 August August August August August September 31 24 12 20 19 September 14 10 19 14 110 September 5 120 19 32 36 September 120 7 20 60 26 September 22 3 5 70 September 12 200 September 4 60 September 37 October 70 30 10 27 60 October 90 15 20 16 10 October 18 20 22 150 41 October 130 10 40 50 50 October 58 100 120 90 100 October 60 120 90 50 October 200 310 50 70 October 170 30 26 October 40 November 20 67 360 120 30 November 140 39 40 70 20 November 24 50 210 70 150 November 190 14 40 35 18 November 46 50 20 10 November 14 200 90 BOIL WATER ADVISORIES & HEALTH RISK IN NL 132
November 120 160 November 70 November 250 December 43 20 70 100 December 120 75 120 25 December 25 120 130 80 December 420 100 23 100 December 20 70 19 20 December 14 28 40 December 40 100 December 30
Giardia Crypto Date (cysts/100 L) (oocysts/100 L) Comments 11-Oct-06 0 0 24-Nov-08 0 0 tap sample- Newfoundland Dr., PCR 24-Jul-12 0 0 method tap sample- Musgrave St., PCR 24-Jul-12 0 0 method
BOIL WATER ADVISORIES & HEALTH RISK IN NL 133
Table B4: Pathogenic source water quality data for Corner Brook, Corner Brook Lake supply Total Giardia Crypto Coliform E. coli (cysts/10 (oocysts/ Turbidity Temp (CFU/10 (CFU Date 0 L) 100 L) (NTU) pH (oC) 0 mL) /100 mL) 1991-1995 3-Jul-97 22 7 26-Aug-97 44 25-Sep-97 26 23-Oct-97 14 4-Jan-99 2 16-Jun-99 4 3-Sep-02 650 10 12-Nov-02 12 24-Aug-04 580 10 19-Jun-06 140 10 4-Jul-06 500 10 8-Jul-06 550 10 18-Jul-06 10 30-Aug-06 640 10 12-Sep-06 560 10 12-Sep-06 480 10 12-Dec-06 2.1 0 3 7.16 4 3-Jan-07 2.1 0 3 7.03 3 16-Jan-07 2.9 0 3 7.44 2 28-Jan-07 1.1 0 2 6.8 3 15-Aug-07 1270 60 15-Aug-07 1040 20 22-Jul-08 870 160
BOIL WATER ADVISORIES & HEALTH RISK IN NL 134
Table B5: Pathogenic source water quality data for Botwood, Peter’s River supply
Total Coliform Date (CFU/100 mL) E. coli (CFU/100 mL) 1991-1995 25-Jun-03 90 10 30-Nov-04 360 30 1-Sep-04 2560 10 27-Jul-04 920 10 31-May-05 320 0 1-Sep-05 780 10 1-Nov-05 110 50 25-Jun-03 90 10 30-Nov-04 360 30 1-Sep-04 2560 10 27-Jul-04 920 10 31-May-05 320 0 1-Sep-05 780 10 1-Nov-05 110 50
BOIL WATER ADVISORIES & HEALTH RISK IN NL 135
Table B6: Pathogenic source water quality data for Gander, Gander Lake supply
Date 4-Sep-12 Total Coliforms (CFU/100 mL) 38 E. Coli (CFU/100 mL) 0 Volume Filtered (L) 68.1 Giardia (cysts) 0 Mean Giardia Recovery (%) 44 Crypto (oocysts) 0 Mean Crypto Recovery (%) 47 Turbidity (NTU) 0.52 Water Temp ( oC) 19.4 pH 6.9
Total Coliform E. coli (CFU/100 Date (CFU/100 mL) mL) 10-Jun-97 360 170 13-Aug-97 760 50 03-Dec-97 460 70 13-May-98 660 20 19-Aug-98 560 200 15-Dec-98 260 60 02-Feb-99 480 120 25-Apr-02 220 60 18-Jun-02 900 200 15-Sep-03 2400 40 31-Aug-04 300 100 19-Mar-03 500 160 26-May-04 460 90 31-Aug-04 3000 410 18-May-05 160 32 29-Aug-05 3100 100 05-Nov-05 310 90 BOIL WATER ADVISORIES & HEALTH RISK IN NL 136
24-May-06 120 15 04-Jul-07 4 10 21-Aug-07 100 10 15-Jul-08 30 0 08-Sep-08 690 20 14-Jul-09 5200 300
BOIL WATER ADVISORIES & HEALTH RISK IN NL 137
Table B7: Pathogenic source water quality data for Heart’s Delight-Islington, Long Pond supply Date 28-Aug-10 Total Coliforms (CFU/100mL) 9403 E. Coli (CFU/100 mL) 3 Volume Filtered (L) 38 Giardia (cysts) 0 Mean Giardia Recovery (%) 42 Crypto (oocysts) 0 Mean Crypto Recovery (%) 46 Turbidity (NTU) 1 Water Temp ( oC) 20 pH 6.84
Table B8: Pathogenic source water quality data for Clarenville, Shoal Harbour River supply Date 27-Aug-10 Total Coliforms (CFU/100mL) 2420 E. Coli (CFU/100 mL) 220 Volume Filtered (L) 79.5 Giardia (cysts) 0 Mean Crypto Recovery (%) 42 Crypto (oocysts) 0 Mean Crypto Recovery (%) 46 Turbidity (NTU) 0.39 Water Temp ( oC) 17.4 pH 6.09
Table B9: Pathogenic source water quality data for Deer Lake, Humber Canal supply Date Total Coliform (CFU/100mL) E. coli (CFU /100mL) 19-Jul-06 260 10 13-Sep-06 80 10 29-Jul-09 >80 60
BOIL WATER ADVISORIES & HEALTH RISK IN NL 138
Table B10: Pathogenic source water quality data for Cox’s Cove, Cox’s Brook supply Date Total Coliform (CFU /100mL) E. coli (CFU/100mL) 15-Aug-07 1500 200 19-Sep-07 240 10 22-Jul-08 280 20
BOIL WATER ADVISORIES & HEALTH RISK IN NL 139
Appendix C: Epidemiological data on enteric waterborne illness in Newfoundland
and Labrador
BOIL WATER ADVISORIES & HEALTH RISK IN NL 140
Table C1: Laboratory confirmed cases of enteric illness in NL by region (2006-2011)
Verotoxigenic Rotavirus Escherichia Year Region Campylobacteriosis Cryptosporidiosis Giardiasis Infection coli 2006 Eastern 23 2 16 27 - Central 11 - 6 5 - Western 8 - 8 4 - Labrador- GF 1 - 5 2 - Total 43 2 35 38 0 2007 Eastern 31 1 18 23 7 Central 9 - 2 4 1 Western 7 - 3 24 1 Labrador- GF 1 - - 10 1 Total 48 1 23 61 10 2008 Eastern 23 1 30 7 3 Central 7 - 2 3 - Western 3 - 1 5 1 Labrador- GF - 1 12 3 - Total 33 2 45 18 4 2009 Eastern 21 2 13 33 2 Central 7 - 3 14 2 Western 4 - 3 12 - Labrador- GF - - 5 16 - Total 32 2 24 75 4 2010 Eastern 27 1 8 6 - Central 7 - 5 1 - Western 5 - 11 1 - Labrador- GF - - 11 - Total 39 1 35 8 0 2011 Eastern 40 - 9 1 5 Central 12 - 5 3 1 Western 9 3 21 10 - Labrador- GF - - 8 8 - Total 61 3 43 22 6
BOIL WATER ADVISORIES & HEALTH RISK IN NL 141
Table C2: Annual laboratory confirmed cases of enteric illness in NL (1979-2011)
Year Population Giardiasis Cryptosporidiosis Campylobacteriosis E. Coli 1979 557,720 30 1980 557,720 45 1981 567,681 53 1982 567,681 48 1983 567,681 83 1984 567,681 50 1985 567,681 46 1986 568,350 61 1987 568,350 58 1988 568,350 40 1989 568,350 49 123 1990 568,350 46 130 1991 568,474 208 102 7 1992 568,474 167 87 13 1993 568,474 71 135 7 1994 568,474 80 123 6 1995 568,474 67 89 12 1996 552,156 42 101 2 1997 552,156 42 110 1 1998 552,156 54 214 7 1999 552,156 55 109 7 2000 552,156 64 1 74 3 2001 512,930 45 2 87 5 2002 512,930 35 0 45 9 2003 512,930 29 1 56 4 2004 512,930 29 0 57 2 2005 512,930 22 86 5 2006 505,469 35 2 43 0 2007 505,469 23 1 48 10 2008 505,469 45 2 33 4 2009 505,469 24 2 32 4 2010 505,469 35 1 39 0 2011 514,536 43 3 61 6 BOIL WATER ADVISORIES & HEALTH RISK IN NL 142
Appendix D: Reference Material from Health Canada’s QMRA Model (version
11_07) 1
1 From QMRA_CrypGiardiaRotaCampyEcoli (Version 11_07) [software], by Health Canada, 2011, Ottawa: Health Canada. Copyright 2011 by Health Canada. Reprinted with permission. BOIL WATER ADVISORIES & HEALTH RISK IN NL 143
BOIL WATER ADVISORIES & HEALTH RISK IN NL 144
BOIL WATER ADVISORIES & HEALTH RISK IN NL 145
BOIL WATER ADVISORIES & HEALTH RISK IN NL 146
BOIL WATER ADVISORIES & HEALTH RISK IN NL 147