Home > Nanotechnology Columns > Neil Gordon > America Needs a New Strategy for Safe Drinking Water
An estimated 19.5 million Americans, representing about 7% of the entire US population, got sick last year from drinking water containing pathogenic bacteria, viruses and parasites. Countless more consumed water with cancer-causing chemicals, radioactive substances, and nuclear materials. Pathogens and toxins are ending up in tap water from ineffective treatment of contaminated source water, infiltration of contaminants through broken water mains, an absence of government regulations that require drinking water to be adequately tested for multiple pathogens and hundreds of toxic materials, and a lax enforcement of regulations by government officials that allowed over 94% of Clean Water Act violators to avoid fines or significant punishments. Current trends suggest that the problems will intensify. An increase in America's population and related water-intensive industries such as food processing will require even more contaminant-free water, while at the same time pristine water sources are depleting.
Maintaining the status quo will likely lead to a greater number of illnesses from an aging population with an increasing number of sick, immuno-compromised, and malnourished who are less able to fight off pathogens and toxins. This will place a greater burden on the health care system. Rebuilding under-capacity water treatment plants and deteriorating water distribution infrastructure will take decades and approach a trillion dollars nationally in the next 20 years. A more cost-effective solution is to implement a new generation of nanotechnology-based inline sensors that rapidly detect a diverse suite of pathogens and toxins, along with updated regulations and meaningful enforcement. This will allow water operators to more quickly identify dangerous contaminants and take actions to prevent contaminated water from reaching consumers. With a network of sensors providing precise information about the sources of infiltration, water administrators would be able to prioritize major infrastructure projects by measuring the potential health benefit versus the cost of prospective investments.
May 2nd, 2010
America Needs a New Strategy for Safe Drinking Water
How safe is America's water?
The quality of America's water was described in a series of articles by Charles Duhigg of the New York Times. According to Charles, "an estimated 19.5 million Americans fall ill each year from drinking water contaminated with parasites, bacteria or viruses." The occurrence of illnesses from drinking water is 10 times higher than the 1.8 million reported cases combined from all 54 notifiable diseases in the US listed in C.D.C.'s Morbidity and Mortality Weekly Report. At the current rate each American will get sick from drinking pathogens in their water on average once every 15 years and 5 times in their life. Because we are dealing with averages, some people will get sick more than 5 times and some less often, and the severity of illnesses will vary from person to person. People can become extremely sick by swallowing just few living pathogens since they rapidly reproduce once inside a host organism.
Charles also reported that "Americans become sick from swimming in waters containing the kind of pollution often linked to untreated sewage, including 4 million swimmers last year just in California." This comes to about 11% of California's population. Illnesses can also result unknowingly when pathogens are consumed by eating fresh fruits or vegetables washed in contaminated water, showering in water transmitting pathogens previously collected on showerheads, or breathing air containing contaminated water droplets sprayed from cooling towers, mist machines, humidifiers, whirlpool spas, and hot springs.
The above statistics for drinking water illnesses from pathogens do not include the effects of consuming poisonous chemicals, radioactive substances and nuclear materials (CRNs) found in drinking water. Unlike pathogens which make people sick in days or hours, toxic CRNs cause cancers and diseases in years and are more difficult to link to water. The National Research Council of the National Academies reported that "the identified number of waterborne disease outbreaks is considered an underestimate because not all outbreaks are recognized, investigated, or reported to health authorities."
Something is severely wrong when so many people get sick each year after consuming potable water that meets safety standards set by E.P.A. for water treatment, distribution, and testing. The high morbidity rate clearly indicates that there are major flaws in the US public water system, which is considered to be among the safest in the world.
Contaminants are surviving water treatment plants
Chlorination is the most common method used to sanitize pathogens in drinking water. Chlorination can give a false sense of security as parasites such as Cryptosporidia and Giardia lamblia, and viruses like Hepatitis A and E, Rotavirus, Norovirus, Poliovirus and Echovirus can be viable even when water is chlorinated. Chemicals used for chlorinating water can produce carcinogenic by-products like trihalomethanes (THMs) and haloacetic acids (HAAs) which could be more dangerous to human health than the pathogens which were intended to be killed. Chlorination levels can be reduced to minimize by-product production but this also lessens the ability to kill bacteria.
Other sanitation methods such as ultraviolet (UV) radiation, ozonation, and ultrafiltration are effective on all types of pathogens, although ozonation can produce bromated trihalmethane, another carcinogen, and ultrafiltration requires expensive filters to be regularly cleaned and/or changed. Unlike chlorination, these alternative methods are not cheap as they require a lot of energy to use.
Water treatment plants are principally designed for sanitizing pathogens and most have limited capabilities for treating the wide range of CRNs that could be present in water sources. Most municipalities have treatment plants designed for specific source water compositions that existed long before changes in population and industry. This leaves drinking water vulnerable to many new CRNs that began entering the water decades after the treatment plants were built.
Contaminants are infiltrating aging and poorly maintained water mains
Contaminants can enter the drinking water supply through openings in broken pipes that deliver treated water to consumers. Cities with aging or broken water mains, new developments that have left dead ends in the old water network, and pipelines connected to wells can allow contaminants to access the water supply. Michael Cooper of the New York Times reported that "there are 240,000 water main breaks every year in the United States. Pipes installed after World War II have an average life of 75 years." Some mature cities. such as "Washington, DC where the average water main age is 76 years" according to Charles, have as much as 50% of its pipes exceeding their useful life and are at high risk of rupturing.
Pathogen sources can include storm runoff, industrial and agricultural by-products, leaking septic tanks, untreated waste from infected animals and people, and cemeteries. In 2000, heavy rains brought livestock manure laden with E.coli O157:H7 and Campylobacter jejuni bacteria into Walkerton, Ontario's water supply. Half of the town's 5,000 residents were sickened and 7 died. Following the incident, it was found that 25 miles of the town's pipeline were filled with biofilms that became a breeding ground for E.coli and other pathogens to obtain nutrients and reproduce. E.coli contained in biofilms are extremely resistant to chlorine, and can be released into the drinking water distribution network when there is a significant pressure change in the water system caused by an industrial plant turning on a production process or a fire hydrant being opened. Contamination from cross-connections and back-siphonage is a major cause of contaminants spreading through the distribution network.
Drinking water treatment plants using UV and ozone sanitation provide no protection against pathogens that infiltrate the water distribution network, whereas chlorine compounds reside in the water and continue to disinfect. Therefore a single sanitization method can have limited benefits for killing pathogens.
Regulations do not require testing for numerous pathogens and hundreds of toxic chemicals
The E.P.A. does not require drinking water to be tested for pathogens even though pathogens sicken 1 in 15 Americans each year. E.P.A.'s more limiting regulation, the Total Coliform Rule (TCR), calls for the monitoring of total coliforms, fecal coliforms and/or generic E.coli. These indicator organisms do not detect the presence of parasites, viruses and non-fecal bacteria which make up the majority of the waterborne pathogens listed by the World Health Organization.
TCR also requires a minimum number of water samples be taken based on the population being served by a water system. This varies from 1 water sample per month for populations under 1,000, to 1 or more samples per day for every 100,000 people served. Based on an average of 2 daily test samples per 100,000 people, a mandated water sample size of 0.026 gallons (100 milliliters), and 242 million people served by the public water system, then approximately126 gallons of water are sampled per day. Compared with the 43 billion gallons supplied each day, there are about 3 gallons of water sampled for every billion gallons of water used to meet the TCR regulation. This sample size can be compared to testing 20 people from the world's 6.6 billion population, and is so small it is statistically limited in value.
To put the sample size in perspective, if as little as 1/10th of 1% of the 43 billion gallons of daily water was contaminated and pathogens were undetected from the 126 gallons collected, then 43 million gallons of contaminated water would be distributed through the public water system every day. This may account for the large number of pathogen illnesses.
One of the reasons for the incredibly low sampling rate is the high cost to travel to each sampling station and then collect, transport, prepare, incubate, culture and interpret water samples. The decades-old cell culturing technology for detecting Coliforms or indicator E.coli can take several days or weeks to get results and then repeat the steps to confirm a positive reading. As treated drinking water can reach consumers in little as 6 to 18 hours, contaminated water will be consumed long before the test results are known. Real time instruments are available for measuring turbidity and counting particles but cannot distinguish pathogens from harmless heterotrophic bacteria or other materials present in the water that can outnumber pathogens by a million to 1.
Regarding the testing for chemicals, Charles reported that "only 91 contaminants are regulated by the Safe Drinking Water Act, though more than 60,000 chemicals are used within the United States. Governments and other scientists have identified hundreds of chemicals that are linked to diseases in small concentrations that are either unregulated in drinking water or are policed at limits that pose serious health problems."
Violators of water regulations are not being held accountable
In terms of the effectiveness of existing regulations, Charles cited that "the Clean Water Act has been violated 506,000 times since 2004, by more than 23,000 companies and other facilities. Fewer than 6 percent of all Clean Water Act violations and fewer than 8 percent of water systems that violated the arsenic and radioactive standards resulted in fines or other significant punishments by state or federal officials."
The Clean Water Act covers drinking water supplied to 62% of Americans. Charles added that "the remaining 38% or 117 million Americans get their drinking water from sources excluded from the Clean Water Act. This leaves 45% of major water polluters outside of regulatory reach from spilling oil, carcinogens and dangerous bacteria into lakes, rivers and other waters, and not being prosecuted."
The future clearly points to water quality getting worse
The major trends impacting water quality include the following:
• Demand for clean water is increasing - With greater life expectancy and needed immigration, the US Census Bureau projects the country's population will increase from the current 307 million to 392 million by 2050. A larger US population will require more drinking water, more clean water for food production, which is the biggest use of water, and more industrial water. As there are less pristine water sources available, Americans will need to make greater use of polluted source water for drinking and food. Reclaimed water with raw sewage is increasingly added to drinking water when clean source water is in short supply, as in Orange County, California. Efforts to reduce water consumption through conservation, and to develop new sources such as desalinating ocean water, are unlikely to offset the rise in demand.
• More contaminants are entering the water supply - As a result of a larger population, more waste will be returned to the water supply. This includes human feces, feces from farm animals, manure for crops, output from slaughterhouses, rotting food and compost, industrial biowaste, decaying forests, pesticides, pharmaceuticals, industrial chemicals, by-products from power plants, fluids from cars, trucks and airplanes, discarded batteries, arsenic, heavy metals and more. Livestock is a particular concern as liquid manure is typically untreated and if not properly managed, live pathogens can end up in source waters used for drinking. According to an Organisation for Economic Co-operation and Development (OECD) publication, raw manure shed by farm animals contains the following range of pathogens: pigs (5 - 20% Cryptosporidium, 7 - 22% Salmonella, 1 - 10% Yersinia, 1.5 - 9% pathogenic E.coli); cattle (13% Salmonella, 3.5% pathogenic E.coli); calves (20 - 90% Cryptosporidium, 57 - 97% Giardia); sheep (8 - 40% Cryptosporidium, 4 - 15% Salmonella, 2% pathogenic E.coli); poultry (9% Cryptosporidium); and waterfowl (13 - 100% Cryptosporidium , 6 - 50% Giardia, 1 - 10% Campylobacter).
• Capacity of water treatment plants and distribution networks cannot keep up with demand - Drinking water and wastewater treatment plants and water distribution networks can barely keep up with demand in many cities. Charles reported that "rain causes a rising tide throughout Brooklyn's sewers, where untreated feces and industrial waste overwhelm treatment plants and spill into the Upper New York Bay. Sometimes all it takes is 20 minutes of rain to get overflows across Brooklyn." Severe storms, tornados and hurricanes have overwhelmed the water system in many cities such as New Orleans which was infiltrated with pathogens after Hurricane Katrina. The increased use of recycled wastewater and new pollutants such as human growth hormones will further stress an already overworked water system, along with its plant operators and regulators.
• More people living in the US will be vulnerable to illnesses and diseases - With an increase in population including elderly, immuno-compromised, poor, malnourished, and illegal aliens with existing health problems, there will be more people in the US who are unable to fight off illnesses from pathogens and toxins. When Cryptosporidium entered Milwaukee's water system in 1993 and caused a cryptosporidiosis outbreak that resulted in over 400,000 cases of serious illness, most of the 100 deaths were AIDS patients. A greater population of vulnerable people will directly lead to an increase in illnesses and diseases including deaths linked to consuming waterborne contaminants.
Safe drinking water options are expensive and limited
The simplest course of action is to maintain the status quo. The current 19.5 million illnesses from drinking water containing pathogens, plus additional illnesses and cancers from other contaminants will very likely increase when more vulnerable people consume a greater amount of contaminated water. With the US government taking over health care responsibilities, the additional financial burden and negative publicity from outbreaks should make the status quo unsustainable in the coming years.
Safe drinking water responsibility can potentially be passed on from government agencies to consumers by mandating the home use of water sanitizing devices, testing kits, and/or bottled water. While Point-of-Use water sanitizing devices are becoming more popular among the affluent and health conscious, it is very unlikely that the poor and vulnerable who need clean water the most can afford to pay the additional costs for securing their own safe drinking water by giving up other essentials. Bottled water, which can be over 100 times more expensive than tap water, is not a cost-effective alternative. A lack of regulations for bottled water along with the added pollution from discarded plastic containers, make bottled water an unattractive alternative to tap water.
Another option is to invest in new water treatment plants and distribution infrastructure. Charles reported that "a significant water line bursts every two minutes somewhere in the country. For decades, water systems - some built around the time of the Civil War - have been ignored. $335 billion would be needed to maintain the nation's tap water systems in coming decades. Another $400 billion in extra spending is needed over the next decade to fix the nation's sewer infrastructure." While actual costs tend to be higher than estimates, plus new water systems like desalination of ocean water may be needed to provide additional clean source water, the real price for new infrastructure might be approaching $1 trillion in the next 20 years. Charles also reported that "it will take 300 years to replace Washington DC's water network with current water taxes. This would be reduced to 100 years with an increase in water taxes that DC voters do not want." Unless a considerable amount of money can be committed and supported by taxpayers, a critical mass of new infrastructure is unlikely.
A faster and less costly way to reduce the incidence of drinking water illnesses is to deploy a network of inline sensors that rapidly detect a large number of specific pathogens and contaminants. With this timely information, water plant operators can take appropriate actions to prevent contaminated drinking water from reaching consumers.
Automated instruments would sample and test water throughout the distribution network and eliminate the need for technicians to manually collect samples and then transport water to laboratories for time-intensive testing. Automated sampling and testing would shave days off of current methods. Inline pathogen and CRN sensors would also test a much greater volume of water by collecting larger samples, and conducting tests more frequently and at more locations to greatly exceed current regulations. Permanent sensors would be placed in strategic locations in the distribution network and mobile sensors would be used to pinpoint the sources of infiltration so expensive infrastructure work and immediate repairs could be prioritized.
To be cost-effective, sensors would detect multiple pathogens and contaminants at the same time rather than indicator organisms in single culture tests. Test results would be sent electronically to water utility operators for rapid action, and posted online as soon as validated results are available so consumers could gain visibility about the safety of their drinking water and violators could be held accountable.
Following a decade of research, breakthroughs in nanotechnology-based biosensors and chemical sensors are around the corner and will be available for commercial use in the coming years. These sensors are activated by a biological or chemical reaction when target materials are present in the water and cause a change in properties such as mass, temperature, oxygen content, color, or electrical current.
Low concentrations of dangerous contaminants produce minute changes in properties that can be measured by the extremely sensitive nanotechnology-based sensors. Because of their tiny size, many nano-sensors can fit on the same device to allow multiple pathogens and toxins to be detected at the same time. Sensor outputs can converted to electrical signals and communicated wirelessly to operators and allow them to take immediate actions to prevent the spread of contaminants before they reach consumers. As a result, a new option is available in the coming years that can have a major impact on reducing drinking water morbidity, health care costs, and water sampling and testing costs.
Morbidity impact and cost factors favor inline multi-pathogen and CRN sensors
An estimate is provided below of the relative costs for drinking water actions and the associated impact on morbidity rates.
Relative costs and impact on morbidity rates for drinking water actions
Nanotechnology-based inline sensors that rapidly detect a diverse suite of pathogens and toxins offer a new cost-effective method for safe drinking water. Field instruments making use of pathogen and CRN nano-sensors will allow water operators to more quickly identify dangerous contaminants and take actions to prevent contaminated water from reaching consumers. With a network of sensors providing precise information about the sources of infiltration, water administrators would be able to prioritize major infrastructure projects by measuring the potential health benefit versus the cost of prospective investments.
Government has a key role to play by being the early adopter of these emerging sensing technologies and implementing new regulations that mandate the frequent testing of a comprehensive suite of pathogens and CRN toxins. With the onset of further illnesses, it is a matter of time before the water industry takes advantage of automated sensing technologies that have benefitted many other manufacturing and service industries worldwide.
President & CEO
Copyright 2010 © Neil Gordon
The author thanks Garry Palmateer for his comments and review.