In an announcement issued today, GNWT’s Chief Environmental Health Officer Dr. Chirag Rohit reported that laboratory-based testing from the hamlet of Fort Liard, reviewed by the Office of the Chief Public Health Officer, shows that the total THM levels in treated drinking water are above Health Canada’s guidelines.
Health officials said the risks are considered “minimal” but are advising precautions for those who live in Fort Liard, in order to reduce exposure to Trihalomethanes (THMs) in drinking water.
“This advisory is precautionary. The health risk is considered minimal, as only longterm (over 70 years) exposure to THMs is expected to cause serious illness.
The main THM found is chloroform. Health effects from chloroform happen at much higher levels above 1,400 micrograms per litre. THM levels in Fort Liard have likely been higher for some time, but they have never reached the level where chloroform could cause health effects. The average values of total THM for the community are around 139 micrograms per litre,” said the Chief Environmental Officer.
Officials said the THMS are being produced as a byproduct of chlorine reacting with other materials that are present in the water.
“THMs form when chlorine reacts with natural organic material in water. Factors such as changing climate and water composition cause higher organic materials, and aging infrastructure limits the ability to remove organic materials,” said Dr. Rohit.
Dr. Rohit reported that in October, the Hamlet of Fort Liard and Municipal and Community Affairs began implementing short-term measures to reduce THMs. Dr. Rohit added that work is ongoing towards a “long-term solution.”
In the meantime health officials are advising residents to use an NSF/ANSI 53 certified water filter that is equipped to remove THMs.
“Look for the words “Trihalomethane or THM removal” on the box. Filters can be pour-over, countertop, faucet mount, or under-sink.”
Officials are advising to follow the instructions on the filter and change the filter according to the instructions.
Alternatively, there are precautionary steps people can take without the use of a filter by filling a pitcher with tap water and leaving it uncovered in the fridge for 24 hours before drinking.
According to the advisory, some THMs will leave the water into the air.
Officials said another option is to use bottled water.
The Chief Environmental Officer is advising the public to not drink water straight from a lake or river.
Officials offered the following advice for food preparation:
• Use filtered or bottled water for cooking.
• Tap water can be used to wash fruits and vegetables.
• When boiling or steaming, ventilate the kitchen to reduce vapour exposure.
Shower, Bath and Housekeeping Use
• Tap water can be used for brushing teeth, washing hands, and laundry.
• Keep showers under 10 minutes and baths under 30 minutes. Open a window or use a fan as a THMs can evaporate into the air during bathing.
Shorter showers and ventilation can help reduce exposure.
Anyone who would like more information can head to GNWT’s advisory webpages
• Questions about the drinking water advisory in Fort Liard
• Disinfection by-products in drinking water
• Questions And Answers On Drinking Water Treatment Devices – Canada.ca
Hay River, Enterprise, Kátł’odeeche First Nation and Ka’a’gee Tu First Nation (Kakisa) continue to be under THM advisories since early November, but the THM levels have reported improved in the last weeks.
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