The NWT’s chief environmental health officer has issued an advisory to Fort Liard residents over elevated levels of chemicals known as trihalomethanes in local drinking water.
Trihalomethanes, or THMs, were in the news lately because of a similar advisory for South Slave communities including Hay River.
High levels of THMs can come when chlorine – used to disinfect drinking water – reacts with organic material such as decaying plants and algae.
“Factors such as changing climate and water composition cause higher organic materials, and ageing infrastructure limits the ability to remove organic materials,” the NWT government stated in Monday’s advisory.
The GNWT said recent lab tests showed THM levels in Fort Liard’s treated water are above Health Canada guideline levels.
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“This advisory is precautionary. The health risk is considered minimal, as only long term (over 70 years) exposure to THMs is expected to cause serious illness,” the territory stated.
“The main THM found is chloroform,” the statement continued, adding that the amount in the water has “never reached the level where chloroform could cause health effects.”
The hamlet has been working to reduce THMs in the water since October, the GNWT stated, and “work continues on a long-term solution.”
In the meantime, the territory issued a list of steps residents can take to help reduce the level of THMs in water they drink.
In Hay River, officials have said recent tests show THMs are now below the guideline maximum. However, the annual average must also drop below that level before the all-clear can be issued.
The earlier advisory for South Slave communities included a note that, over a span of seven decades, THMs had been associated with a potential increase in the risk of cancer. The advisory for Fort Liard did not contain that terminology, and nor did a GNWT-issued Q&A for Fort Liard residents, referring instead to a risk of “serious illness” over many decades’ exposure.
