For more than 100 years, chlorine has helped protect people across the country from dangerous pathogens that may otherwise lurk in their drinking water. But in some communities, byproducts of that same disinfectant may be putting residents in harm’s way.
The water delivered to homes in some B.C. communities — including Prince Rupert in the north and parts of the District of Lake Country in the Okanagan Valley — has for years contained elevated levels of possibly cancer-causing contaminants called trihalomethanes.
A byproduct of the treatment process, trihalomethanes, or THMs, form when chlorine reacts with organic matter in the water.
Studies have linked long-term exposure to THMs to increased risks for pregnancy complications, spontaneous abortion, slowed fetal growth, gastrointestinal disease, some cancers and damage to the kidneys, liver and central nervous system.
Avoiding exposure isn’t as simple as drinking bottled water. THMs can be absorbed through the skin and inhaled. Even washing dishes, swimming in a pool, taking a shower or bathing can contribute to overall exposure.
Reporters from the University of British Columbia, representing a consortium of universities and media companies across Canada, including Concordia University’s Institute for Investigative Journalism, the Star Vancouver and Global News, collected samples of tap water from 16 homes in the coastal City of Prince Rupert in December and had them tested by an accredited lab.
THM levels exceeded Health Canada’s guideline of 100 ppb in water from every house.
In Florbela Cunha’s home, the THM levels were 162 ppb.
“It’s concerning,” said Cunha, a mother to two young sons and a teenage daughter. “It’s a health issue.”
Cunha, whose water also contained elevated levels of lead, said her family doesn’t drink much water from the tap anymore after learning the results from the lead and THM testing. But she’s worried that doesn’t protect them from exposure to THMs altogether.
“It’s concerning that it’s airborne,” she said.
Elevated THMs aren’t a new issue in Prince Rupert, a city of almost 12,000 people on B.C.’s north coast. A government report published in 2005 noted that a Northern Health official had recommended ongoing monitoring of THM levels in the region back in 2002, and the city’s own routine sampling, reported in annual drinking water reports, shows elevated levels as far back as 2014.
High THM levels can indicate one of two things.
“One, maybe there is more chlorine inside the water, unused,” said Haroon Mian, a research assistant at the University of British Columbia, who specializes in water quality management and distribution. “Or second, maybe there is more organic matter … from the source that is coming in.”
Surface water sources such as lakes and rivers are vulnerable to organic matter such as decaying leaves and other vegetation. If that debris isn’t removed from the water through filtration, it can interact with leftover chlorine to create disinfection by-products like THMs.
Despite reports of discoloured water and years of elevated THMs, Prince Rupert doesn’t currently filter its water as part of its treatment process.
“Chlorination is the city’s only current method of disinfection, which protects our population against serious waterborne diseases,” said Veronika Stewart, a spokesperson for the city, in a statement.
“Health Canada acknowledges that, ‘The health risks from disinfection byproducts, including trihalomethanes, are much less than the risks from consuming water that has not been disinfected,’” she said.
But Prince Rupert and Northern Health do work to limit the amount of disinfection by-products such as THMs by using the minimum amount of chlorine to disinfect the water, and the city is planning a new treatment facility that will eventually filter organic materials out of the water to address elevated THMs, Stewart said.
THMs are a concern elsewhere in B.C. as well.
In Lake Country, a district municipality in the Okanagan, THMs have been a persistent issue in drinking water pulled from two lakes.
Lake Country, which has a population of about 13,000 people, draws its drinking water from four different lakes and treats it with chlorine. Water from two — the Beaver and Oyama lakes — have for years exceeded Health Canada’s guideline, which is based on an average of at least four quarterly samples.
In 2018, the average THM levels in water from Beaver Lake was 237 ppb, more than double the federal guideline. THM levels in the water from Oyama Lake similarly measured 236 ppb, based on two samples.
About 1,250 households and other users get their water from Beaver Lake, according to the district. Another 280 households and other users get their water from Oyama Lake for at least part of the year.
Susan Duncan, a spokesperson for Interior Health, said the health authority is concerned any time a water provider reports THM exceedances.
“THM concentrations for water from the Beaver and Oyama Lake sources will be addressed as the district improves the treatment on their water supplies to incorporate treatment processes that will decrease the THMs in that water supply,” Duncan said in a statement.
The THM levels in water from Beaver and Oyama lakes are higher during the spring melt, said Karen Miller, a spokesperson for the district in a statement, adding that the two water systems are under continuous water quality advisories.
“Every community wants and deserves a reliable, sufficient supply of clean, safe water,” she said.
The District of Lake Country has undertaken infrastructure projects to reduce reliance on water from these lakes, particularly during this time of year.
“During spring freshet these systems are supplied with water from Kalamalka Lake or Okanagan Lake for as long as possible,” Miller said.
“One of the District’s next major capital improvement projects, as identified in the District’s Water Master Plan, is construction of a water treatment facility which will keep THM’s in the distribution systems low throughout the year,” she added.
Six water systems within Island Health’s region also reported exceedances of disinfection byproducts in 2018/2019, according to a government spokesperson. But it’s unclear just how many communities across B.C. are dealing with elevated levels of THMs.
Most health authorities aren’t able to “reliably provide” the Office of the Provincial Health Officer with information on the number of water systems that exceed Health Canada’s guidelines for disinfection byproducts, government spokesperson Meribeth Burton said in a statement.
It’s largely an issue with data management. Currently, most health authorities can’t directly upload the data they get from water suppliers or labs to their databases, she explained.
“Some (health authorities) manually enter in some of the chemical sample data received, others keep the results in a file folder for the water system,” Burton said.
“Given the sheer number of systems and results, not all (health authorities) are able to retrieve this data for reporting purposes to the (provincial health officer).”
That should change in the next five years, according to Burton, who noted the provincial health officer has asked regional health authorities to find a way to report this information.
In the meantime, residents can turn to the annual water reports released by their municipalities for information.
Chlorine is commonly used as a disinfectant in the water treatment process throughout B.C. and across Canada. According to a federal technical document, “the use of chlorine in the treatment of drinking water has virtually eliminated waterborne diseases, because chlorine can kill or inactivate most microorganisms commonly found in water.”
Water utilities have to strike a balance between protecting citizens’ health with disinfection, while minimizing exposure to the potential health risks of disinfection byproducts.
Not all have been able to do this. Nationwide, disinfection byproducts are an insidious problem.
Dozens of communities in Newfoundland and Labrador exceed federal health guidelines for THMs, and, in July, elevated levels of THMs and haloacetic acids caused Attawapiskat First Nation in northern Ontario to declare a state of emergency.
In Prince Rupert, where drinking water is drawn from a nearby lake, some residents said the water is often yellow or brown, and sometimes contains debris.
The Gruber family, which owned Saanich Plumbing and Heating Ltd. for 35 years, sold a lot of filters to customers wanting clearer water, said Rob Gruber.
Get more stories like this one in your inbox
Take your time with the Star’s biggest and best features with our Weekend Long Reads email newsletter.
“There are lots of organics in the water. It gives it a kind of a yellow tinge, especially if you’re filling a tub or something large, you can really notice it,” said Gruber, whose water also tested high for THMs.
In 2014, at one site in the city’s distribution system, the annual drinking water report recorded THM levels in quarterly water samples that averaged 117 ppb. In 2017 the average of five samples from that same site had soared to 167 ppb.
Prince Rupert’s high THM results could cause serious health effects if consumed regularly over the long-term, Mian said.
“At this level we are talking about, mostly, the cancer risk,” he said. “I would say: liver, kidney, central nervous system damage.”
Reducing the amount of organic matter in the water can significantly reduce the level of THMs.
But, “some drinking water systems lack infrastructure and equipment for effectively removing the organic matter that are in the form of decaying vegetation,” Duncan, the spokesperson for Interior Health noted in a statement. Interior Health serves B.C.’s southern Interior, including Lake Country.
“These infrastructure improvements require significant investments and sometimes funds are not readily available to drinking water operators to immediately implement those needed changes,” she said.
“As smaller water systems are financially under-resourced, treating THMs can be technically difficult and very expensive,” said Jessica Quinn, a spokesperson for Northern Health, in a separate statement.
Using a single form of treatment though, goes against recommendations from both federal and provincial governments.
“The most effective way to manage drinking water systems is to implement a multi-barrier approach,” reads a 2002 report from a federal-provincial-territoral drinking water committee. “The goal of this approach is to reduce the risk of contamination of the drinking water, and to increase the feasibility and effectiveness of remedial control or preventative options.”
Notes taken during a routine inspection by Northern Health in July 2018 noted three different “inadequate treatment” violations in Prince Rupert, including one for THM exceedances.
While THM levels were above Health Canada’s guidelines, reducing the chlorine residual wasn’t considered a solution, as it would “put public health at a greater risk associated with microbial contamination,” according to the city’s 2018 drinking water report.
Prince Rupert was cited for another inadequate treatment violation because its “water system is not meeting drinking water treatment objectives for surface waters in BC, which requires two treatment processes for surface water.”
Aside from the potential health risks of long-term exposure to elevated levels of THMs, reliance on chlorine treatment alone can leave water supplies vulnerable to parasites.
In December, Prince Rupert experienced its first city-wide boil water notice in more than a decade over what appeared to be unacceptable levels of the parasites cryptosporidium and giardia in the water. Chlorine can’t get rid of cryptosporidium on its own.
The notice stretched through Christmas, lasting six weeks before being downgraded to an advisory for babies and children under the age of two, the elderly and people with weak immune systems.
In March, Prince Rupert released a post-incident report assessing their response to the boil water notice. The report claimed that the lab mistook algae for cryptosporidium.
“There is no way to confirm this theory, as the original samples have been discarded,” read the report.
During the boil water advisory, many residents resorted to buying water or taking a 20-minute drive to the neighbouring community of Port Edward.
With a population of just 500 people, Port Edward is much smaller than Prince Rupert. Despite its size, the district invested in a new water treatment facility, completed in 2004, to address organic matter in its water supply, and high levels of disinfection byproducts, as reported by former Northern View reporter Shannon Lough in January.
Other nearby communities have also taken measures to address disinfection byproducts and other water quality issues, including Metlakatla First Nation, where an upgraded water treatment facility began operating in 1994 to address water issues similar to Prince Rupert’s.
The two water samples collected in Metlakatla as part of this investigation showed THM levels under the federal guideline. One sample from the daycare had a THM level of 51 ppb. Another collected from the last house in the distribution system, which was unoccupied at the time, had a THM level of 81 ppb.
Cunha, who grew up in Prince Rupert and is now raising her family there after spending 12 years in Vancouver, said she’s glad the city is moving forward with a plan to improve water treatment, but she’s concerned it’s moving too slowly and questions why it’s not more of a priority.
Other small drinking water systems in B.C. are still dealing with elevated THMs as well, including the Cove Bay Water System on Bowen Island. While Bowen Island Municipality didn’t follow Health Canada’s quarterly sampling protocol, it notes that “individual results in 2016 and 2017 indicate that an annual average of quarterly samples may exceed guidelines for THMS.
Test results show THM levels ranged between 90.1 and 211 ppb in samples taken between January 2016 and December 2017. Of 10 samples, just one was below the guideline of 100 ppb, another was 102 ppb, and the rest came in above 125 ppb.
Bowen Island Municipality is building a new treatment plant that will remove organic matter through filtration and should help reduce THM concentrations. But it’s unclear how many other water systems in B.C. need similar upgrades.
Earlier this year, B.C.’s Auditor General Carol Bellringer raised “grave” concerns about a lack of accountability for the provision of safe drinking water in the face of increasing and varied threats.
The auditor’s report notes that “as no single form of treatment can eliminate all potential health hazards, multiple barriers of protection … are normally necessary to ensure that drinking water is safe.”
The Ministry of Health has treatment objectives for water systems, but the auditor found the ministry “had not determined how many systems are out of compliance with these objectives, and therefore had not identified high-risk treatment facilities.”
The Provincial Health Officer has recommended that the ministries of health, municipal affairs and housing, and regional health authorities work together to review water systems and identify which ones aren’t meeting treating objectives.
“This review will inform the development of financial plans and compliance processes to meet the treatment objectives, and will help identify where resources are best directed to achieve identified target dates for improvements,” the Provincial Health Officer recommended.
In a statement, a government spokesperson, said, “In a situation where average THM levels frequently exceed the guidelines, water suppliers should work with health authorities to look at strategies for reducing THM levels, recognising that major infrastructure changes often take several years to implement.”
In the meantime, concerned homeowners can install activated carbon or reverse osmosis systems at the tap or treatment systems for the whole home to reduce exposure to chlorine and disinfection byproducts, according to a fact-sheet from Vancouver Coastal Health and Bowen Island Municipality.