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The Truth About Chilliwack Water Chlorination

The Truth About Chilliwack Water Chlorination

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Despite exceptional efforts by the City of Chilliwack to ensure the safety of the City’s drinking water, bacterial contaminants, specifically E. Coli, have repeatedly entered the water system.  As a result, under the authority of the Drinking Water Protection Act, Fraser Health has advised the City of Chilliwack to activate its Secondary Disinfection on the water system.  This means adding chlorine to the water system to prevent deadly E.Coli out-breaks.

The Provincial Health Officer published a report: Drinking Water Quality in British Columbia: The Public Health Perspective.  This report provides information on current drinking water quality issues including the regulation and management of B.C.'s water systems, Canadian and international water quality guidelines and scientific evidence to guide public health decisions on safe drinking water.

Questions at a glance
How is water monitored for E. Coli and fecal contamination?
What exactly is “secondary disinfection”?
I heard that chlorine causes cancer?
Can I develop an allergy to chlorine?
Under what authority can Fraser Health order the city to chlorinate the water?
Isn’t there something else we can do to safeguard the water system?
How much will this system cost?
What does "confirmatory testing" mean?
What does a "low level" of E. coli mean?

Can the citizens of Chilliwack vote on whether or not the water is chlorinated?

Who can I contact if I have further questions?

So much is being said about “good” or “bad” E. Coli.  What is it and why should I be concerned?
Answer
E. coli is a type of bacteria that is found in the stomachs of human and animals.  Human and animal waste, or feces, contains E.coli as well as other bacteria and viruses which can make people very sick.  This includes symptoms ranging from mild stomach upsets and diarrhea to kidney failure and in rare cases, death.  All strains of this bacteria are dangerous – some more than others.  In fact, strains such as O157:H7, have been responsible for large waterborne outbreaks of disease in Canada, including several deaths (Walkerton).  It is simply a question of protecting the health and safety of the residents of Chilliwack.  No amount of E. coli, or other fecal organisms in our water, is acceptable.
How is water monitored for E. Coli and fecal contamination?
Answer

Currently, water is sampled from various points in the system and sent to the Provincial Laboratory for testing once a week.

However, the turnaround time for getting results from the lab can be two days.  This means that if a contamination event occurred just before a scheduled sample was taken, people would be drinking contaminated water for at least two days before we would know about it.  With once weekly sampling, the lag time before a contamination event was detected could be up to eight days.  Increasing the frequency of sampling would not lower the minimum lag time below two days.

In addition, a city the size of Chilliwack uses an enormous amount of water and we can only test less than one millionth of the water, as such only a small amount of water is sampled.  Also, sampling by itself is not a very sensitive way to detect contamination events.  This means that any detection of E.coli is very significant “warning bell” and needs to be addressed decisively.

Chilliwack has won awards for the best water in the world.  Why is Fraser Health questioning this?
Answer

E.coli has been detected three times since 2009 in parts of the Chilliwack water system.  Other bacteria found in feces were also found in the Chilliwack water several times in the years prior to 2009.  Each time E. coli or fecal bacteria are detected, it is a warning that there is a potentially serious problem.

The water from the Sardis Vedder is of excellent quality coming out of the ground.  The place where problems are likely to occur is in the distribution system, which has 450 km of water mains, 17 reservoirs, over 20,000 service connections and is growing.  Sources of contamination may include breaks in the system, leaking pipes, valves or seals, illegal connections and backflows, intrusions into reservoirs by humans or animals, fire flow conditions and vandalism.  Many of these sources of contamination can be difficult to detect the way the Chilliwack water system is monitored right now.

What was done about the E. coli during these events and why can’t we just keep doing the same thing?
Answer

The Chilliwack water system already has the capacity to chlorinate the water so when E.coli was found in the past, the chlorinators were turned on to kill the E.coli.  Public Works also conducted extensive investigations to find the source of contamination and to fix it.  Afterwards, the chlorinators were turned off.

As the city of Chilliwack grows, the complexity of the water system and the risk of contamination events also increase.  Each time we detect E.coli, it is like a “warning bell” for the water system and we have heard it ring repeatedly, despite the problems being fixed each time.  This means that a measure like chlorination is necessary in order to protect the public safety.

If E.coli is only found in a few places at certain time of the year, are people living in the rest of Chilliwack at risk?
Answer
Yes. Bacteria grow faster and are easier to detect when it is warm and in areas where there is less flow. Consequently, we usually detect E.coli during the summer and in areas with less flow volume.  This does not mean that E. coli and other harmful bacteria are not present in the rest of the system, just that we can’t detect them.  Sources of contamination exist throughout the system and chlorination of the entire system is required to safeguard all residents.
I’ve lived in Chilliwack my whole life and have never been sick because of the water.  Why should I worry now?
Answer

The primary goal of Public Health is to prevent cases of illness before they occur.  The old saying “An ounce of prevention is worth a pound of cure” is the rationale behind many of our services including maternal health programs, food safety and immunizations.

In Chilliwack we want to take effective and decisive action before a large E. coli outbreak can occur.  In other waterborne E. coli outbreaks, cases of illness were not detected in the period before the catastrophic contamination occurred.

Even when people do get gastroenteric illnesses like diarrhea, it is usually not reported Public Health because they do not go see a doctor and stool samples are seldom taken to identify a cause.

What exactly is “secondary disinfection”?
Answer
Secondary disinfection with chlorine means that chlorine is added to the water as the final step in purification. Since contamination can occur anywhere in the distribution system, chlorine needs to be present throughout the entire system. The chlorine kills disease-causing bacteria and viruses in the water and gradually dissipates. Because extremely low amounts of chlorine stay in the water until it leaves the tap, these bacteria and viruses cannot grow back. After leaving the tap, the chlorine quickly evaporates. Secondary disinfection is safe and effective and used in virtually all cities in North America and the developed world. In Canada, secondary disinfection is an industry and government standard for all public water supplies. Another benefit of chlorination is that chlorine levels can be easily and accurately monitored in real time. Modern sensing equipment can securely relay this information directly to the water system operators, wherever they are, on their cellular phones. A sudden drop in chlorine levels can tell the water operators that there is a breach in the system (ie. a potential contamination event) and exactly where it is, any time of night or day. This is much more sensitive and timely than water sampling alone.
I love the taste of my water.  Will adding chlorine to it change the way it looks and tastes?
Answer

No. Chlorine sometimes changes the colour or taste of water because it reacts with decaying and dissolved plant material which is always present in surface water supplies like lakes and streams.  Chilliwack’s water comes from an aquifer, so there is no plant material present in the water to react with the chlorine.  In some cases, chlorinated water may be even clearer than un-chlorinated water because bacteria have been removed.  Since the city’s chlorinators have been turned on several times in the past few years, you may have already drank chlorinated water without even knowing it.

For those with more sensitive taste buds, a simple filter can be added to the tap (like Brita) which will eliminate the remaining trace amounts of chlorine.

I heard that chlorine causes cancer?
Answer
According to the Canadian Cancer Society website, chlorine is a strong chemical, but the chlorine itself is not the main cause for concern in drinking water. When chlorine interacts with organic matter (such as dead leaves and soil) in untreated water, it forms new chemicals that remain in the water. These are called chlorination or disinfection “by-products” (DBP). It is thought that perhaps these chlorination by-products can increase cancer risk. There are some inconclusive data that this link may be real for bladder cancer in particular.

As there is some uncertainty surrounding the cancer risk, regulatory agencies have erred on the side of caution and have set maximum guideline levels for these DBPs in drinking water at a level way below what is known to be safe. This ensures any DBP in a potable water system are safe for human consumption over many years.

Chilliwack’s water comes from an aquifer, so there is no plant material present in the water to react with the chlorine, therefore very little risk of chlorination “by-products”. Monitoring of the hillside area which has been chlorinated for many months has failed to detect any level of byproducts in the system at all.

For decades, researchers have studied the long-term effects of using chlorinated tap water but more research is needed.
Can I develop an allergy to chlorine?
Answer

In some cases, conditions that are called allergies, both by the public and doctors, are irritational syndromes where a chemical irritates the skin or mucosa in people who are especially sensitive to that substance. These syndromes may present with similar symptoms as allergies, but tend to come and go and are reversible.

An allergy is a specific immune response by the body to something which is normally not harmful (ie. an allergen), resulting in symptoms. Allergens are usually plant or animal proteins found in foods or in the environment, but are not components of the human body.

Chlorine is an essential electrolyte in the human body and is a component of all bodily secretions, so allergies to chlorine do not exist.

However some people, such as lifeguards, professional cleaners and competitive swimmers, may develop sensitivities after prolonged exposure (ie. more than 1000 hours) to higher concentrations of chlorine, such as those found in swimming pools. These sensitivities may include skin or respiratory tract irritation.

The level of chlorine in drinking water is 0.2 parts per million while levels in swimming pools are at least five to fifteen times higher. The very low levels of chlorine in drinking water are extremely unlikely to cause any sensitivity reactions.

Under what authority can Fraser Health order the city to chlorinate the water?
Answer

Fraser Health’s mandate is to ensure the health and well-being of the population it serves.  Fraser Health does not make the laws; it has a responsibility to enforce them.

Under Section 6 of the Drinking Water Protection Act, a water supplier must provide drinking water that:
(a) is potable water, and
(b) meets any additional requirements established by the regulations or by its operating permit.
The section of the Act regarding requirements for the Operating Permit, enable the Health Authority to specify treatment obligations.

Isn’t there something else we can do to safeguard the water system?
Answer

Fraser Health has been working with the community for several years now, trying to use other methods to safeguard the water system.  Unfortunately, in spite of these efforts, there have been a number of E. Coli incursions, putting the population at unnecessary risk.  These incursions have even included contamination of wells as far back as 2003.

While there are several options for Secondary Disinfection including ultra-violet, ozonation and filtration, chlorination continues to be the most viable and desirable for a water system of this size.  In order for these alternatives to be effective, they must be placed at the point of use, that is, where the water comes out of the tap.  This means that all 80,000 users must comply, making this a costly option.

How much will this system cost?
Answer
The Chilliwack water system was installed with a modern chlorination system and they have the capacity to operate all the time.  It is simply a matter of turning them on.  A continuous monitoring system would eventually have to be installed; however chlorine levels could be monitored manually in the short-term.  There would be ongoing costs for chlorine and monitoring supplies; however these should be seen as necessary upgrades and expenses to maintain an adequate and safe drinking water in a growing community.
Is it possible that the E. coli contamination events are the result of sampler or laboratory error?
Answer

It is extremely unlikely that the repeated detection of E. coli in the Chilliwack water system is the result of error. 

Chilliwack has taken a number of steps to reduce the likelihood of such errors including comprehensive training and maintenance of competencies for water operators, rigorous and standardized sampling procedures, and sampling sites which are dedicated and protected from intrusion or incidental contamination. 

The sampled water is tested at the provincial laboratory at the BC Center for Disease Control. The laboratory is approved and accredited and follows the strict protocols outlined in the Enhanced Water Quality Assurance Program (EWQA). In addition, sampler and laboratory errors can often be detected because they show certain patterns of bacterial growth or involve strains of organisms present in other tests in the same lab. The water samples from Chilliwack have none of these feature. All samples have been taken, stored, transported and tested according to protocol and are considered valid and accurate.

What does "confirmatory testing" mean?
Answer
When a water sample comes back positive for E. coli, immediate action is taken because no amount of E. coli contamination is safe. Samples are taken again at the same site, as well as the surrounding area to gauge the amount and extent of contamination. Chlorination is then promptly started to make the water safe to drink. In large contamination events the repeated and expanded tests will also be positive, however in small contamination events the tests may be negative even though E. coli has already entered the water system. Even if the repeat tests are negative, a thorough investigation needs to be conducted to find the source of the contamination and steps taken to ensure that the water is, and remains, safe to drink.
What does a "low level" of E. coli mean?
Answer
This is not a term used by water operators, public health or doctors because no amount of E. coli contamination is safe. In small contamination events, a small amount of E. coli may be diluted by a large amount of water. So there may be a low liklihood that you will be the one to drink the E. coli. However if you do ingest the contamination, the risk is high.
Can the citizens of Chilliwack vote on whether or not the water is chlorinated?
Answer

The Drinking Water Protection Act is a piece of provincial legislation and is not within the authority of either the municipality or the health authority to change or overrule.

Changing the legislation would require a motion to the BC Provincial Legislature and a majority vote by all representatives of the population of BC.

Who can I contact if I have further questions?
Answer
Call us at 604-870-7917 or email us at waterquestions@fraserhealth.ca.

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