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Controversy over Gander water treatment change

Switch to chloramine disinfection worries residents

Town of Gander water reservoir

Town of Gander water reservoir (Leigh Anne Power/CBC)

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Some residents of Gander have made formal complaints to the town council about a change in the community's water system.

The town has traditionally used chlorine to disinfect the drinking water, but recent rapid growth of the community is straining the infrastructure. Last year, test results showed the level of chlorine at homes farthest from the water treatment plant was dangerously low. Bacteria was re-growing without enough chlorine, which put the residents at risk.

 "The big concern was on two separate occasions we were very close to a boil water advisory," said James Blackwood, Gander's chief engineer.

"That was something we as council and we as staff didn't want to face. We've got a state of the art water treatment plant and we didn't want to be heading for a boil water advisory or putting anyone at any sort of risk for e-coli."

To solve the problem, the town council decided to switch to using chloramines as a secondary disinfecting agent, after the primary ozonation method.

Chloramines are formed by mixing chlorine with ammonia. Municipal water systems use monochloramine, which is an unstable compound that easily converts into two other forms; dichloramine and trichloramine — which can have different effects on people and on the environment.

'People noticed skin problems right away'

That's what's got some Gander residents worried. They're asking some of the same questions as concerned water users across North America.

Town of Gander water supply system

Town of Gander water supply system (CBC/Leigh Anne Power)

Linda Corwin is with the Citizens Concerned about Chloramines action group in the United States.

"What happened with us, I was in the San Francisco Bay area in 2004 when they put chloramine in our system. People noticed skin problems right away, and asthma increased. Nine months later, our water heaters started exploding out the bottom because the release valve was too corroded to release the pressure. And that's when we formed our group," she said.

Experts concede erosion of lead and copper plumbing is a side-effect of using chloramines, although they're gentler on steel than chlorine.

Some studies show there can be breathing problems caused by inhaling chloramine vapors, similar to those created by mixing bleach and ammonia in cleaning products, in enclosed shower spaces or swimming pools.

Health Canada approves the use of chloramines because they reduce the level of by-products caused by chlorine mixing with organic matter, such as trihalomethanes and haloacetic acids, or THMs and HAAs, which have links to cancer over the long term. Chloramines also last longer and cover more distance in water systems because they don't evaporate like chlorine, which is why Gander is switching.

Few studies on impact on human health

However, Health Canada also admits there haven't been many studies on chloramines and their impact on human health.

Water flows from tap in Gander

Water flows from tap in Gander (CBC)

Environment Canada warns chloramines are toxic to fish, and fish owners must use special filters to protect their aquariums. There have also been large fish kills connected to effluent containing chloramines.

Blackwood says that's something Gander is striving to avoid.

"I know it can happen. It's also a concern that our wastewater is discharged to a freshwater environment. And that's something the Department of Environment will be working on with us to make sure it's dissolved as it's released to the environment."

"Probably the biggest concern will be during our flushing program, when we discharge huge amounts of water in a short period of time. So we're looking at different devices we can put on there, different chemicals or tablets to make sure that's dissolved prior to its release into the environment," he said.

Tougher to remove in individual homes

Dialysis units have to be extremely careful to make sure the chloramines in local water are removed.

Health Canada cites one case in Ontario, in which 41 patients needed blood transfusions to repair red blood cell damage caused by chloramines making it into their blood streams.

While slow filtration through active carbon can remove chloramines for dialysis, it's tougher to remove them in individual homes. Traditional water filters or evaporation techniques don't work. Vitamin C filters do the job, but they're used up quickly and expensive to replace.

After a pilot project last fall, Gander is going to go ahead with chloramine disinfection permanently, despite residents' concerns. Blackwood says it's a proven, safe method of purifying drinking water.

Many communities across the country, including St.John's, which has been injecting the Bay Bulls Big Pond reservoir water with chloramines since 1978, use them without controversy.

Gander is currently looking for proposals for the conversion of the system. There's no timeline or cost estimate for the project so far.

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