An Apologia or Why I Wrote This Book
An economist should write a book on water resource and drinking water management to highlight the critical intersection of economic principles and sustainable water practices By applying economic theory, one can advocate for the efficient allocation of water resources, ensuring access to clean and healthy drinking water for all Furthermore, the principles of supply and demand, externalities, and cost-benefit analysis are essential in promoting not only human health but also the vitality of ecosystems Ultimately, integrating economic insights into water management can lead to policies that support both public health and environmental sustainability.
Modern agricultural, mining, and industrial activities have improved citizens' well-being but have also created negative externalities, which are unaccounted social costs Economists argue that government intervention is necessary to address these externalities for the benefit of society and future generations When the government fails to implement adequate control and regulation, it leads to environmental degradation and issues with drinking water quality This book is motivated by the concerning record of waterborne disease outbreaks, highlighting inadequacies in how we manage, pay for, and dispose of wastewater affecting our drinking water sources The lack of effective government response to these externalities reflects a decline in its role in promoting social welfare.
The core principle of economics is to achieve the "social good," often understood as a "competitive equilibrium" where negative externalities are absent or addressed through effective government intervention.
Note that this social good does notnecessarilyinvolve redistribution of income to enhance wellbeing of some, or invoke theRawlsian difference principle for a
“liberal” society (Rawls 1971) That of course requires an activist State Our © Springer International Publishing Switzerland 2015
M.H Dore, Global Drinking Water Management and Conservation,
Economic theory is grounded in minimal libertarian principles, emphasizing the necessity of state intervention to address violations of property rights, particularly in cases where public property is misused to the detriment of current and future generations (Dore 1998) This perspective aligns with the concept of a "night watchman state," as suggested by Nozick (1974), which is foundational in standard neoclassical economic thought The Coasian approach, which advocates for negotiation to resolve externalities (Coase 1960), is often viewed as a legalistic addition to economics, gaining recognition when Ronald Coase received the Bank of Sweden Prize in 1991 However, this negotiation framework fails when the affected party is "society" or future generations, rendering the Coase theorem inapplicable In contrast, traditional economic theory offers effective tools for addressing negative externalities, such as corrective taxes and regulations, yet it lacks the political will necessary to enforce these measures.
“socially correct”intervention or solution.
Recent advancements in public economics, stemming from the groundbreaking work of Professor Sir James Mirrlees in the early 1970s, reveal that previously deemed "illegitimate" economic instruments—such as quantity controls, quotas, and forced savings plans—can actually serve as social improvements These tools are justified in an economy characterized by significant distortions and nonlinearities, moving it away from an ideal competitive equilibrium.
Economists, equipped with a strong theoretical foundation and viewing economics as a social and moral science aimed at enhancing societal well-being, are well-positioned to address issues related to water resources and drinking water management This perspective is essential for effectively applying findings from hydrology, limnology, epidemiology, and bio-ecosystem studies to safeguard our environment in the anthropocene era, marked by the detrimental effects of human activities Therefore, the rationale for this book is clear; it aims to utilize economic concepts and statistical methods to critically evaluate existing management practices and social policies, ultimately seeking to improve water policy, particularly in Canada.
Water in a Global Context
Climate Change and Water
A survey by Dore (2005) highlights significant changes in global precipitation patterns Annual land precipitation in the Northern Hemisphere's middle and high latitudes has likely increased by 0.5–1 percent per decade, with the exception of Eastern Asia In contrast, the subtropics (10°N–30°N) have experienced an average decrease in land-surface rainfall of approximately 0.3 percent per decade, although signs of recovery may indicate increased variability Tropical regions have seen a modest increase in land-surface precipitation of about 0.2–0.3 percent per decade throughout the twentieth century, but recent decades show no significant increases, particularly due to the limited land area in the 10°N–10°S latitudes Nonetheless, substantial increases in precipitation have been observed over many tropical ocean areas Changes in annual stream-flow often correlate with total precipitation variations, and the rise in precipitation in Northern Hemisphere mid- and high-latitude regions is closely linked to long-term increases in cloud cover Conversely, no systematic precipitation changes have been identified in the Southern Hemisphere.
Recent satellite data indicates a significant decline in snow cover, with an approximate 10 percent decrease since the late 1960s, closely linked to rising land-surface temperatures in the Northern Hemisphere This correlation highlights the impact of twentieth-century global warming on alpine and continental glaciers, which have shown a major retreat, particularly between 2010 and 2014 While some maritime regions have experienced increased precipitation that mitigates temperature rises, the overall trend reveals a continued shrinkage of glaciers in both the northern and southern hemispheres.
Over the last 100–150 years, observations indicate a likely reduction of approximately two weeks in the annual duration of lake and river ice in the mid- to high latitudes of the Northern Hemisphere Recent analyses reveal that in areas with increased total precipitation, there have been significant rises in heavy and extreme precipitation events Conversely, some regions have experienced an increase in heavy events despite stable or decreased total precipitation, attributed to fewer precipitation occurrences Overall, many mid- and high-latitude regions in the Northern Hemisphere have seen statistically significant increases in the share of total annual precipitation from heavy and extreme events, with a 2–4 percent rise in the frequency of heavy precipitation events noted in the latter half of the twentieth century In the Southern Hemisphere, there are concerns that while extreme precipitation events have escalated, total annual precipitation may have declined.
Between 1900 and 1995, global land areas facing severe drought or wet conditions saw only slight increases, though some regions, particularly in Asia and Africa, have experienced heightened drought frequency and intensity in recent decades These shifts are largely influenced by inter-decadal and multi-decadal climate variability, notably the El Niño Southern Oscillation (ENSO), which has shifted towards more frequent warm events However, there remains significant uncertainty regarding changes in the frequency and variability of El Niño and La Niña events, both of which significantly affect global precipitation patterns Additionally, ocean currents play a crucial role in influencing precipitation worldwide, meaning that any alterations in major ocean currents could lead to substantial changes in rainfall distribution.
Statistical analyses indicate a significant decline in rainfall patterns in dryland regions, particularly since the early 1970s, with a 20 percent decrease in precipitation and a corresponding 40 percent reduction in surface runoff (Council of the European Union, 2007) The International Water Management Institute warns that climate change poses severe challenges to food security for the growing global population, particularly in Africa and Asia, where millions of farmers depend on rainwater for irrigation In Asia, 66 percent of cropland is rain-fed, while a staggering 94 percent of farmland in sub-Saharan Africa relies solely on rainfall (IWMI, 2007) These areas, characterized by underdeveloped water storage infrastructure, are home to nearly 500 million people at risk of food shortages.
The changing patterns in precipitation are clear indicators of global climate change, with the least developed countries facing the most severe impacts Wealthier nations, accustomed to witnessing poverty in the Global South, may perceive the escalating climate-related disasters as familiar challenges rather than urgent crises This disparity highlights a significant inequity, as the consequences of global warming are often viewed as opportunities for voluntary charity rather than a pressing need for compensation from industrialized nations These findings are further validated by the IPCC Fifth Assessment Report (IPCC 2014).
Human actions, alongside advancements in medicine and economic development, are creating contradictory effects on the world's biome Over the next 50 to 100 years, climate change poses a significant threat, particularly affecting water resources Dry regions are expected to become drier, while wet areas will experience increased precipitation, leading to severe flooding, property damage, and loss of life In this challenging environment, human societies must navigate the critical task of ensuring safe drinking water availability.
What This Book Is About
This book explores the comparative management of drinking water in developed countries, which possess the resources to provide high-quality water but often fail to do so, as well as the significant challenges faced by developing nations lacking financial resources and treatment knowledge The crisis in both contexts stems from inadequate public funding for small and rural communities, governmental complacency, and a lack of understanding of water treatment technologies and health risks associated with contaminants While some regions, such as Alberta and parts of Europe, exhibit proactive measures in capital support and technology adoption, a knowledge gap persists regarding treatment costs, risk assessment, and regulatory practices The book emphasizes the importance of a multi-barrier approach to drinking water protection, starting with effective watershed management, and provides a comparative classification of water treatment technologies based on the contaminants they remove, thereby linking treatment efficacy to overall water quality.
To enhance the safety of drinking water, it is crucial to minimize watershed contamination caused by human activities, as outlined in the literature and detailed in Chapters 2 and 6 Additionally, water utilities can significantly improve water quality through effective management of their infrastructure, a topic that is less recognized and is explored in depth in Chapters 7 and 8, focusing on infrastructure asset management that incorporates risk.
In Europe, some major cities manage water supply as a regulated private business, while many regions worldwide rely on local municipalities to provide water as a public good This public approach often lacks profit incentives, which can hinder innovation and advancements in water quality Although European private water companies appear well-managed, their role as innovators in enhancing water quality remains uncertain Evidence suggests that effective government regulation, as seen in Denmark, the Netherlands, and Germany, is crucial for achieving higher drinking water standards Increased public awareness of successful practices in these countries may motivate local governments and utilities to enhance water quality in their own communities.
The production of drinking water exhibits significant economies of scale, favoring large cities while disadvantaging small and rural communities, which often struggle to meet minimum regulatory requirements This disparity impacts the choice of water treatment technologies, with larger cities benefiting from lower disease outbreak probabilities However, long-term health threats, such as lead contamination and harmful disinfection byproducts from chlorine, are frequently overlooked in communities that only meet basic standards Lead in drinking water poses serious health risks, necessitating accurate measurement and regulation, while chlorine disinfection raises concerns due to its byproducts and ineffectiveness against certain pathogens Although newer treatment technologies offer safer alternatives, awareness and government interest appear limited In Europe, there is a greater recognition of these health threats, particularly regarding chlorine use, yet lead contamination remains a pressing issue in many regions Effective solutions include implementing rigorous lead sampling protocols, establishing appropriate maximum contamination levels, and systematically removing lead pipes and fixtures to ensure safer drinking water.
Developed countries have stringent regulations to combat pathogens in water, and with lead now addressed, the focus is shifting towards eliminating chemical contaminants like pesticides, herbicides, pharmaceuticals, and personal care products This challenge is particularly significant when sourcing water from multi-use watersheds, such as the Great Lakes In contrast, Europe has made notable advancements by transitioning from surface water to groundwater sources, which naturally provide a level of treatment and are generally free from contaminants, except for specific known issues like iron and manganese.
Smaller countries such as Denmark and the Netherlands often have the resources to prioritize high-quality water management This article uses Germany, with a population of 82.6 million as of 2014, as a case study to explore effective strategies for enhancing drinking water quality while mitigating long-term risks Germany provides valuable insights for both North America and developing nations on optimal water supply management practices.
This article aims to spark discussions on enhancing drinking water quality globally by drawing lessons from Germany's experiences It seeks to address knowledge gaps and highlight opportunities for improvement, making it relevant for water system owners, managers, engineering consultants, and regulators worldwide Additionally, the comparative analysis may attract readers interested in how different jurisdictions manage water supply as a vital public service.
In "The Problem of Social Cost," Coase (1960) explores the implications of externalities on economic transactions, emphasizing the importance of property rights in resolving conflicts Dore (1998) presents a libertarian perspective on rights, particularly concerning the ethical considerations for future generations Additionally, Dore (2005) examines the impacts of climate change on global precipitation patterns, highlighting the current understanding of these environmental shifts and their potential consequences.
Dore M, Simcisko P (2013) Projecting future climate scenarios for Canada using general circulation models: an integrated review In: Younos T, Grady C (eds) Climate change and water resources Springer, Berlin, pp 3 – 27
Dore M, Singh R (2013) Projected future precipitation scenarios for a small island state: the case of mauritius In: Younos T, Grady C (eds) Climate change and water resources Springer, Berlin, pp 47 – 66
The European Union emphasizes the importance of energy efficiency and renewable energy sources, as highlighted in the conclusions of the Brussels European Council held on March 8-9, 2007 Additionally, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) warns that climate change and desertification pose significant risks to over a billion impoverished individuals, underscoring the urgent need for action to address these global challenges.
IPCC (Intergovernmental Panel on Climate Change) (2014) IPCC fi fth assessment report (AR5). http://www.ipcc.ch/report/ar5/ Accessed 25 May 2014
IWMI (International Water Management Institute) (2007) Water for food, water for life: a comprehensive assessment of water management in agriculture Earthscan/IWMI, London/ Colombo
Margat J (2008) Les eaux souterraines dans le monde, 1st edn UNESC/BRGM, Paris
The Global Land Degradation Information System (GLADIS) serves as a vital database for assessing land degradation on a global scale, as highlighted in the technical report by Nachtergaele et al (2010) published by the Food and Agriculture Organization of the United Nations Additionally, Nozick's influential work, "Anarchy, State, and Utopia" (1974), explores complex philosophical concepts regarding governance and societal structures.
Rawls J (1971) A theory of justice, 1st edn Belknap Press of Harvard University Press, Cambridge, MA
UN-DESA (United Nations, Department of Economic and Social Affairs, Population Division)
(2009) World population prospects: the 2008 revision, highlights, working paper no ESA/P/ WP.210
The UN-HABITAT report from 2006 highlights the importance of addressing water and sanitation issues in small urban centers to meet development goals It emphasizes the critical role that proper water management and sanitation facilities play in improving living conditions in cities worldwide The publication serves as a valuable resource for understanding the challenges and strategies related to urban development and infrastructure For more information, visit the UN-HABITAT website.
The WHO and UNICEF report from 2010 highlights advancements in sanitation and drinking water, focusing on the Joint Monitoring Programme for water supply and sanitation The document provides essential data and insights into global progress in these critical areas, emphasizing the importance of safe water and sanitation for public health For more detailed information, refer to the publication available on the WHO website.
The United Nations World Water Assessment Programme (WWAP) published the fourth edition of the World Water Development Report in 2012, focusing on the management of water amidst uncertainty and risk This report, which includes essential facts and figures, is a crucial resource for understanding global water challenges It was released by UNESCO in Paris and can be accessed through their official document repository.
Waterborne Disease Outbreaks and the Multi-barrier Approach to Protecting Drinking Water
Introduction
Recent global drinking water outbreaks have led to various illnesses and fatalities, prompting a review of microbial contaminant incidents and the lessons learned Focusing on the most relevant cases for policy, this chapter builds on the findings from Hrudey and Hrudey's 2004 publication, "Safe Drinking Water: Lessons from Recent Outbreaks in Affluent Nations," which documented 69 outbreaks from January 1974 in Richmond Heights, Florida, to March 2002 in Transtrand, Sweden Their work notably highlights the Walkerton contamination in 2000 and the insights gained from these events This chapter aims to incorporate outbreaks that have occurred since 2002 and further explore the conclusions drawn by the Hrudeys, enhancing our understanding of drinking water safety.
Waterborne outbreaks are primarily caused by contaminants such as Cryptosporidium parvum, Giardia lamblia, Campylobacter jejuni, and Escherichia coli (E coli), which are the main focus due to their significant impact While Toxoplasma gondii is also a pathogen of concern, it poses a much lower risk These contaminants typically enter water sources through fecal matter from humans or animals Drinking water can be affected by three categories of microbial contaminants: protozoa, bacteria, and viruses, with protozoa and bacteria being the most impactful Outbreaks arise from various factors, and the multi-barrier approach is a key strategy for improving drinking water safety, utilizing multiple checkpoints to ensure high water quality and mitigate contamination risks.
M.H Dore, Global Drinking Water Management and Conservation,
The multi-barrier approach is essential for detecting and treating contaminants before they reach consumers, as failures in these barriers can lead to outbreaks of contamination Historical data shows that most drinking water outbreaks stem from these failures, which can occur at any point in the system, including source water, operations, treatment, and distribution Such outbreaks highlight weaknesses within water systems, reflecting poorly on their capacity to provide safe drinking water Weather events, particularly heavy rainfall and spring melt, can introduce contaminants into water sources, with surface water being more susceptible than groundwater due to its accessibility and lower natural filtration Despite advancements in water system management aimed at reducing outbreaks, contamination remains a significant global issue, affecting even developed nations like Canada, the United States, and Europe.
This chapter begins with an overview of protozoan contaminants, specifically focusing on Cryptosporidium, Giardia, and Toxoplasma, followed by an examination of bacterial contaminants such as Campylobacter and E coli Each contaminant is described along with the major outbreaks they have caused Additionally, Section 5 reviews key principles of watershed management.
Protozoa
Cryptosporidium
Cryptosporidium is a common microbial agent responsible for drinking water outbreaks, primarily due to its resistance to chlorine disinfection, which allows it to spread undetected in water distribution systems While chemical disinfection is vital for preventing contamination, alternative treatments such as coagulation, sedimentation, filtration, ozone, and ultraviolet light are essential for effectively combating Cryptosporidium Communities that depend solely on chlorine are particularly susceptible to cryptosporidiosis, a disease characterized by severe diarrhea Most outbreaks stem from treatment failures, often linked to an over-reliance on chlorine and inadequate filtration Filtration is crucial for removing Cryptosporidium, especially in areas using surface water sources, which are more prone to environmental contaminants Consequently, cryptosporidiosis is most prevalent in communities that utilize surface water without proper filtration measures.
In May to July 1984, Braun Station, Texas, experienced a significant outbreak of cryptosporidiosis, linked to a chlorinated groundwater source contaminated by sewage This outbreak resulted in 2,000 reported illnesses among a population of around 5,900 The failure to implement effective treatment measures, specifically the absence of filtration capable of removing Cryptosporidium—an organism resistant to chlorine—was a critical factor in the outbreak.
In early 1987, Carrollton, Georgia faced a significant outbreak of cryptosporidiosis, resulting in over 13,000 reported cases of illness The contamination stemmed from surface water sources that were compromised, affecting approximately 27,000 residents in a county with a total population of 64,900 Investigations suggest that the source of the contamination was likely due to fecal runoff from nearby grazing cattle and sewage overflow from upstream into the river.
1996, p 79) Conventional treatment was used prior to the outbreak, which includes coagulation, flocculation, sedimentation, filtration, and chlorination Improper
Flocculation, a critical step in the water filtration process, contributed to the spread of contaminants in the distribution system, highlighting a significant failure in the treatment process (Rose, 1997) This incident underscores the necessity for adequate filtration and monitoring, as the operators failed to identify and rectify the malfunctioning flocculation system In response to the outbreak, Carrollton upgraded its treatment system by installing new flocculators, enhancing filter monitoring, and improving chemical dosage and operational practices (Solo-Gabriele and Neumeister, 1996) These upgrades represent essential advancements aimed at preventing future water contamination.
In early 1992, Jackson County, Oregon, faced a significant cryptosporidiosis outbreak, resulting in 3,000 confirmed cases and an estimated 15,000 affected individuals The contamination originated from two water supplies: Medford, serving 70,000 residents, sourced its water from Big Butte Springs, treated only with chlorine, while Talent's system, serving 3,000 people, utilized a river source treated through multiple processes The contamination in Medford was likely due to polluted surface water, while Talent's river was believed to be affected by treated wastewater and potentially agricultural runoff exacerbated by drought conditions System failures contributed to the outbreak, particularly Medford's inadequate filtration and Talent's insufficient response to increased turbidity In response, Medford flushed its distribution system with chlorinated and filtered river water, and Talent implemented necessary repairs and treatment improvements.
In the first half of 1992, North Cumbria, England, faced a cryptosporidiosis outbreak affecting an undetermined number of individuals Approximately one-third of the 160,000 residents received water from Ennerdale Lake, while another third relied on Crummock Lake, and the rest sourced water from smaller supplies The contamination of Ennerdale Lake is attributed to runoff from nearby livestock, and the outbreak was exacerbated by the water treatment process, which only involved chlorination and lacked proper filtration.
Between November 1992 and February 1993, Warrington, England faced a cryptosporidiosis outbreak, with 47 confirmed cases and an estimated 1,840 individuals affected due to contaminated water supplied to 38,000 residents The groundwater treatment relied solely on chlorine, with no filtration, which is typical for groundwater due to natural soil filtration The outbreak's source is believed to be agricultural runoff, exacerbated by heavy rainfall that allowed contaminated surface water from livestock fields to infiltrate the groundwater Research indicates that communities relying on groundwater may have lower immunity to Cryptosporidium, leading to more severe outbreaks compared to those using surface water A significant factor in this incident was the lack of monitoring of the water supply, as Cryptosporidium contamination in groundwater is uncommon, resulting in infrequent pathogen monitoring practices.
The most significant outbreak of cryptosporidiosis occurred in Milwaukee, Wisconsin, from March to April 1993, when two water treatment plants sourcing from Lake Michigan faced contamination The southern plant, which served southern and central Milwaukee, was contaminated in April 1993, leading to its temporary closure until June 1993 During this time, the northern plant had to supply water to the entire area, highlighting the vulnerability of municipal water systems to contamination events Both treatment plants utilized conventional methods, including coagulation, flocculation, sedimentation, and rapid sand filtration.
The Milwaukee outbreak, which resulted in over 403,000 illnesses and 100 deaths among approximately 840,000 water system users, was primarily attributed to contamination from cattle runoff and human sewage in tributary rivers (Solo-Gabriele and Neumeister 1996, p 78) Additionally, some research suggested that recycled backwash waters may have contributed to the contamination (Rose 1997, p 141) Backwash recycling, a common practice to clean filters by reversing water flow to remove trapped particles, aims to conserve water (Rose 1997, p 142) This significant outbreak led to regulatory changes in drinking water standards in the United States, prompting the US Environmental Protection Agency to implement the Surface Water Treatment Rule (SWTR), which mandates disinfection and improved treatment protocols.
The filtration of surface and groundwater affected by surface waters is crucial for water safety (Rose 1997, p 154) Following a contamination outbreak, stricter practices for chemical dosing and filter monitoring were implemented, leading to long-term improvements, including the installation of an ozone disinfection facility This indicates that the previous filtration and monitoring levels were inadequate, as they failed to effectively remove or inactivate contaminants Consequently, these contaminants infiltrated the surface water source and managed to bypass the treatment process, entering the distribution system undetected.
In March 1993, Kitchener/Waterloo, Ontario, faced a significant cryptosporidiosis outbreak, with 1,000 reported cases, after the region of 390,000 residents switched from a Cryptosporidium-free groundwater source to contaminated surface water from the Grand River A new filtration plant was in operation, utilizing conventional treatment methods along with ozonation Unlike other communities that had safely used the river for years, Kitchener/Waterloo's outbreak may be linked to low immunity to Cryptosporidium from groundwater consumption The contamination is believed to have stemmed from recycled backwash waters, which could reintroduce pathogens during cleaning processes This incident highlights the risks associated with large municipalities, contrasting with the typical occurrence of drinking water outbreaks in smaller rural areas.
In 1996, British Columbia faced significant outbreaks of cryptosporidiosis in Cranbrook and Kelowna, resulting in approximately 2,000 and 10,000–15,000 cases of illness, respectively Both cities, relying on surface water sources—Cranbrook from Joseph Creek and Gold Creek, and Kelowna from Okanagan Lake—utilized chlorine for disinfection without filtration, raising concerns about the vulnerability of their water systems to contamination Chlorine is ineffective against protozoan pathogens like Cryptosporidium, highlighting the need for alternative treatments such as filtration The contamination source was attributed to cattle manure runoff, and the reliance on chlorine alone led to the outbreak In response, Cranbrook opted for monitoring rather than filtration, while Kelowna, facing a more severe situation, approved the construction of an ultra-violet (UV) light treatment facility, a proven method to combat protozoa and prevent future outbreaks.
Between May 2000 and April 2001, Northern Ireland experienced three cryptosporidiosis outbreaks in the Belfast Area, resulting in 230, 117, and 129 reported cases, respectively While these numbers may seem small relative to the area's population of around 400,000, the sources of contamination varied: the first outbreak was linked to livestock runoff, the second to human sewage from a septic tank, and the third to wastewater from a blocked drain Despite the use of chlorine for water treatment, it has been shown to be ineffective against the Cryptosporidium pathogen The third outbreak, which had filtration in place, still allowed contaminated water to enter the finished water supply due to the blockage Ireland's reliance on surface water for drinking makes it particularly susceptible to contamination from heavy rainfall and agricultural runoff.
The presence of livestock significantly threatens drinking water safety, with the initial outbreak linked to an animal genotype of Cryptosporidium However, subsequent outbreaks were attributed to a human genotype of the same pathogen, highlighting the diverse sources of contamination (Glaberman et al., 2009, p 271).
In 2002, it was highlighted that the significant risk of contamination from both animal and human fecal matter necessitates ongoing monitoring and treatment of water sources to prevent future outbreaks The occurrence of three outbreaks underscores the deficiencies in Ireland's water system regarding effective monitoring and treatment practices.
Giardia
Giardia is a prevalent cause of waterborne disease outbreaks, similar to Cryptosporidium, leading to symptoms such as diarrhea and abdominal pain This protozoan is resistant to low levels of chlorine disinfection, necessitating higher concentrations and extended contact times for effective treatment, particularly in colder water where resistance is heightened Consequently, relying solely on chlorine disinfection is insufficient to combat the Giardia pathogen; thus, filtration and alternative treatment methods are essential to prevent outbreaks.
A significant early outbreak of Giardia contamination occurred in November
In 1974, Rome, New York, experienced a significant outbreak of illness affecting approximately 4,800 to 5,300 residents, attributed to contamination of the city's surface water supply from Fish Creek, believed to be caused by untreated human waste At that time, the water treatment process relied solely on chloramine disinfection, which involved adding chlorine and ammonia to the water entering the reservoir, with no filtration or sedimentation methods in place This inadequate disinfection approach proved insufficient in preventing outbreaks of giardiasis, highlighting the need for improved water treatment practices.
In late 1979, an outbreak of giardiasis in Bradford, Pennsylvania, affected approximately 3,500 individuals, primarily due to ineffective chlorination treatment of the surface water source, which lacked filtration The contamination is attributed to fecal matter from beavers, known carriers of the Giardia pathogen Insufficient treatment and monitoring practices are believed to have facilitated the outbreak's spread (Hrudey et al 2002, pp 402, 404).
Insufficient chlorine levels, inadequate filtration, and a lack of monitoring for chlorine residuals contributed to the outbreak In response, the municipality constructed a treatment plant equipped with filtration to prevent similar incidents in the future.
In December 1985, a Giardiacontamination outbreak in Pittsfield, Massachusetts, affected 3,800 individuals from a population of 50,265 The contamination was likely caused by fecal matter from infected beavers or muskrats, exacerbated by changes in water treatment at the local plant At the time, the city was transitioning from using two chlorinated but unfiltered surface reservoirs to a new filtration system, leading to the temporary use of a third reservoir This reservoir experienced increased turbidity and low chlorine treatment levels due to a malfunctioning chlorinator, leaving the water susceptible to contamination In response to the outbreak, the water system underwent hyper-chlorination, flushing, and enhancements to chlorine residual levels and contact times.
In 1986, Penticton, British Columbia, faced a significant giardiasis outbreak with over 3,000 reported cases, attributed to a mixed water source of chlorinated but unfiltered ground and surface water The contamination is believed to have originated from animal fecal matter entering the water during spring runoff A critical factor in this outbreak was the failure of treatment processes, as filtration, essential for effectively combating Giardia due to its resistance to low chlorine levels, was not implemented.
Treatment failure is the common thread among the outbreaks of giardiasis, just as with cryptosporidiosis In all the included outbreaks of giardiasis, a lack of
Filtration plays a crucial role in the spread of pathogens through water distribution systems, particularly in communities that depend on surface water, which are more susceptible to giardiasis outbreaks These incidents can occur in both small and large populations, highlighting the necessity for effective alternative treatments beyond just chlorination.
Toxoplasma
Toxoplasma gondii is a rare microbial pathogen linked to only three documented drinking water outbreaks: the first in Panama in 1979, the second in Victoria, British Columbia, Canada, in 1995, and the largest in Brazil in 2002, which resulted in 209 cases of illness This pathogen is resistant to standard chlorine treatment, leading to a lack of vigilance in water systems despite its rarity The Victoria outbreak specifically took place between October 1994 and April 1995.
In 1995, the Humpback reservoir, which supplies water to Victoria alongside the Sooke reservoir, experienced a significant outbreak that led to 110 reported cases of illness However, it is estimated that the contamination may have affected between 2,900 and 7,700 individuals (Aramini et al.).
In 1999, it was determined that the contamination in British Columbia's water system was likely caused by fecal matter from cats or cougars (Aramini et al 1999) Toxoplasma gondii, a protozoan pathogen, exhibits resistance to chemical disinfection methods, which facilitates its spread through the water supply and into consumers' taps The reliance on chloramine for disinfection in the B.C water system has raised concerns about its effectiveness against such resilient pathogens.
Canada experienced its first and only reported outbreak of toxoplasmosis, marking it as the first occurrence of this disease in a developed country This outbreak highlights the role of filtration in allowing the pathogen to survive within its reservoir (Dumetre and Darde, 2003, p 654).
Bacteria
Campylobacter
Campylobacter jejuni is a significant cause of drinking water disease outbreaks, leading to gastroenteritis symptoms similar to those caused by Cryptosporidium and Giardia The primary symptom of Campylobacter infection is diarrheal illness Unlike Cryptosporidium and Giardia, which are protozoan pathogens, Campylobacter is a bacterial pathogen Chlorine disinfection is effective against bacteria, making Campylobacter outbreaks theoretically preventable, yet system failures in treatment processes contribute to their occurrence While Campylobacteriosis is more commonly associated with foodborne transmission from raw or undercooked poultry, there have been notable waterborne outbreaks as well.
In May 1983, a Campylobacteriosis outbreak occurred in Greenville, Florida, affecting a rural community of 1,096 residents The contamination was traced back to the ground water source, which was polluted by animal fecal matter.
In a reported outbreak involving 865 cases of illness, the Campylobacter pathogen contaminated the water supply due to infected bird droppings entering open water towers The system's deficiencies, including an unlicensed operator and inadequate treatment processes, allowed this contamination to go undetected Although the treatment involved pre-chlorination, flocculation, and post-chlorination, insufficient chlorine levels failed to prevent the outbreak Specifically, the pre-chlorinator malfunctioned, causing water to backflow into the post-chlorinator, which did not effectively chlorinate the water before it reached the underground well Overall, equipment failures, operational issues, and treatment inadequacies were key factors in this outbreak, which could have been avoided with proper maintenance of the plant.
In March 1985, Orangeville, Ontario, experienced a Campylobacter contamination in its groundwater source, resulting in 241 reported illnesses The contamination stemmed from surface drainage linked to agricultural activities after significant spring rainfall and runoff At that time, the water treatment system did not require chlorination for deep wells, which, combined with the proximity of animal farming, facilitated the outbreak's spread This incident highlights the critical role of effective treatment in preventing drinking water outbreaks In response to the crisis, chlorination disinfection was subsequently implemented.
In 1998, the Haukipudas municipality in Finland experienced a significant outbreak of campylobacter contamination in its groundwater, affecting around 3,000 individuals in a population of 15,000 The outbreak was traced back to bird droppings that entered the water supply through openings in the water tower A critical factor in this public health crisis was the absence of chlorination in the water treatment process, highlighting the importance of proper water sanitation measures to prevent similar incidents in the future.
While Campylobacteriosis outbreaks are less frequent than those of cryptosporidiosis or giardiasis, Campylobacter remains a significant concern for drinking water safety Effective disinfection methods, such as proper chlorination, can successfully eliminate the Campylobacter pathogen.
Escherichia Coli
Escherichia coli is a notorious drinking water contaminant, highlighted by the Walkerton, Ontario outbreak in 2000, which resulted in over 2,300 illnesses and seven deaths This bacterial pathogen, like Campylobacter, is susceptible to chlorine disinfection, making contamination preventable, especially in smaller rural communities The outbreak was primarily caused by cattle manure runoff due to heavy rainfall and system deficiencies, including human error, as water system managers failed to detect and treat the contamination The Walkerton Inquiry, released in 2002, identified the outbreak's causes and recommended legislative changes to enhance water safety, emphasizing the importance of a multi-barrier approach to prevent similar incidents A recurring issue in drinking water outbreaks is the failure of safety barriers, which allows contaminants to infiltrate distribution systems, underscoring the critical need for improved treatment and operational protocols.
Another case ofE colicontamination occurred earlier in Cabool, Missouri in
In 1989, the rural community of Cabool, with a population of around 2,090, experienced a significant outbreak that resulted in 243 reported illnesses and four fatalities, although it received less media attention than the Walkerton incident The contamination, believed to stem from fecal matter due to sewage issues, was exacerbated by a lack of disinfection following water meter replacements and repairs to broken water mains, which were further compromised by unseasonably cold weather and storm runoff The outbreak highlighted critical system deficiencies, similar to those seen in Walkerton, and underscored the importance of effective treatment and disinfection, particularly chlorination, which could have mitigated the E coli contamination and prevented the outbreak.
Both outbreaks of E coli resulted in loss of life due to contamination, highlighting the critical need for proper treatment, operational practices, and equipment maintenance The outbreaks underscore a common issue with bacterial pathogens like Campylobacter and E coli, as they frequently arise in communities relying on surface or groundwater sources susceptible to surface water contamination and inadequate disinfection.
Lessons from Disease Outbreaks
Drinking water disease outbreaks stem from failures within water systems, primarily due to inadequate treatment and monitoring These incidents highlight the necessity for ongoing vigilance, consistent water quality testing, and effective monitoring in both production and distribution processes Insights gained from outbreaks can enhance understanding of safe drinking water techniques, as evidenced by experiences in Canada, the United States, and Europe In their book, "Safe Drinking Water" (2004), Steven and Elizabeth Hrudey emphasize that a multi-barrier approach is essential for ensuring safe drinking water This approach requires implementing barriers at every stage—source, treatment, distribution, monitoring, and response—to mitigate risks from both human and environmental factors Maintaining a focus on this multi-barrier strategy is crucial for detecting and addressing contamination before water reaches consumers, making it the most effective method for providing safe drinking water.
Effective treatment barriers are essential for ensuring safe water distribution, especially when faced with unknown contaminations The primary goal is to inactivate or remove pathogens before water enters the distribution system Chlorine is widely used as a cost-effective disinfectant, particularly effective against bacterial contaminants like Campylobacter and E coli However, it falls short against protozoan contaminants such as Cryptosporidium, Giardia, and Toxoplasma, with Cryptosporidium being the most resistant These protozoa can bypass standard chlorine treatment, leading to significant outbreaks While it may be challenging to prevent contaminants in natural water sources, implementing effective filtration and disinfection barriers is crucial to mitigate the risk of contamination spread and protect public health.
Hrudey and Hrudey highlight that microbial pathogens are the foremost threat to drinking water safety, with all documented outbreaks stemming from these contaminants The persistence of pathogens in water systems poses significant risks due to their potential for widespread contamination and their ability to evade standard treatment processes Originating from human and animal fecal matter, even high-quality water sources, particularly surface waters, are vulnerable to contamination The authors note the alarming rise of Cryptosporidium since the 1990s, culminating in the Walkerton incident in 2000 Its resistance to chlorine, the primary disinfection method, means that Cryptosporidium remains a critical concern for water safety, and despite extensive research and numerous outbreaks linked to this pathogen, incidents continue to occur.
The Hrudeys also emphasize the effects of achangeon a drinking water system.
An adaptable water system is essential for ensuring safe drinking water, as it can effectively respond to various changes, including weather fluctuations, community dynamics, and water system alterations These changes are significant contributors to many waterborne disease outbreaks, such as the one in Carrollton, Georgia, which often occur following seasonal shifts or severe rainfall linked to climate change.
Human activities, particularly farming, have significantly impacted community changes and water systems, leading to contamination outbreaks Notable incidents occurred in Jackson County, Oregon (1992), Warrington, England (1992), and Galway, Ireland (2007), where agricultural runoff was identified as a primary cause Additionally, shifts in water sources contributed to outbreaks, such as in Kitchener (1993) when the water system transitioned from groundwater to surface water, and in Pittsfield, Massachusetts (1985), during the installation of a new filtration plant These changes highlight the need for increased monitoring and precautions by system operators to prevent potential contamination.
The conclusions by Hrudey and Hrudey (2004), based on outbreaks prior to
The Walkerton outbreak in 2002 should have marked a significant turning point in the history of water contamination; however, subsequent outbreaks indicate that water authorities have not fully learned from this incident Notable outbreaks, such as those in Gwynedd and Anglesey, Wales in 2005, and Galway, Ireland in 2007, highlight the need to expand on the lessons outlined by the Hrudeys in their book By analyzing these recent cases, we can assess whether the patterns of waterborne outbreaks have evolved since Walkerton and identify the contributing factors to their occurrence.
Analysis of reported outbreaks reveals that there are no seasonal patterns; they can occur at any time throughout the year While spring runoff and increased rainfall can contribute to contaminations, over half of the outbreaks studied occurred outside the spring season Additionally, human errors such as improper treatment, insufficient monitoring, and inadequate operator training significantly contribute to these outbreaks.
Outbreaks of waterborne diseases do not adhere to a specific pattern related to the size of water systems Contrary to popular belief, these outbreaks are not limited to small rural areas While smaller towns may experience more frequent incidents due to inadequate maintenance and less efficient water infrastructure stemming from financial constraints, larger systems are not exempt from potential failures.
This survey highlights that waterborne disease outbreaks can affect both large and small communities, as evidenced by Milwaukee's population of 840,000 and North Battleford's 15,000, both experiencing cryptosporidiosis outbreaks The significant difference lies in the impact; larger populations face greater consequences due to the higher number of affected individuals Additionally, outbreaks following the 2000 Walkerton incident demonstrate that even large communities remain vulnerable to contamination.
Communities that depend heavily on chlorine disinfection are particularly vulnerable to water contamination, especially from the protozoan pathogen Cryptosporidium, which can bypass many drinking water systems due to its chlorine resistance Alternative treatments such as filtration, ozone treatment, and UV light are more effective against protozoa The reliance on chlorination in affected communities highlights a significant limitation of chlorine, which also produces harmful disinfection byproducts (DBPs) like trihalomethanes (THMs) through reactions with organic compounds, posing potential long-term health risks.
High levels of chlorine used for disinfection can result in an unpleasant taste that is often disliked by communities To prevent ineffective disinfection and the formation of trihalomethanes (THMs), it is advisable to explore alternative disinfection methods.
Multi-use watersheds face contamination risks from various activities, particularly farming operations that introduce animal fecal matter into water sources Additionally, sewage treatment plants contribute significantly to water pollution Both animal and human fecal matter are primary sources of contamination in drinking water outbreaks As human activity in these watersheds rises, so does the potential for contamination Therefore, it is essential for multi-use watersheds to enhance monitoring and management of their water quality.
Boil water advisories (BWAs) are critical measures issued by local water authorities to prevent disease outbreaks by requiring residents to boil their water before consumption, especially after contamination is detected While BWAs can effectively safeguard public health when a pathogen is confirmed, their continuous use often signals issues with water quality management and can lead to complacency among residents, particularly in small, rural communities that struggle financially to upgrade their systems Unfortunately, prolonged BWAs can result in residents ignoring these warnings, undermining their effectiveness and highlighting the need for proper water treatment and maintenance rather than relying on advisories as a substitute.
The quality of drinking water is a critical global concern, as contamination can happen anytime and anywhere, regardless of the water system's size or season Outbreak patterns highlight chlorine's ineffectiveness against the Cryptosporidium pathogen, the susceptibility of multi-use watersheds, and the shortcomings of frequently overused boil water advisories (BWAs) Proper treatment remains essential for ensuring safe drinking water.
The first step in preventing waterborne disease outbreaks is the establishment of protection for source waters, which is a key component of the multi-barrier approach This involves creating a watershed protection plan supported by legislation Effective watershed protection requires a solid understanding of watershed management principles, which are essential for risk management in this context.