North Bay, Ont., and DND move to remediate 'forever chemicals' site that contaminated drinking water

The City of North Bay, Ont., and the Department of National Defence (DND) are set to begin a $20-million project this spring to remediate a site contaminated with perfluoroalkylandpolyfluoroalkylsubstances (PFAS) often referred to as "forever chemicals."

From the early 1970s to mid-1990s,DND conducted training exercises atthe city'sJack Garland Airport with aqueous film-forming foams that contain PFAS.The foams seeped into the groundwater and contaminated wells and Trout Lake, the source of the municipality's drinking water.

"These activities were conducted according to the accepted practices and regulations of the time," DND spokesperson Kened Sadiku said in an email to CBC News.

PFAS are a family of some 14,000 different substances that are characterized by a stable carbon-fluorine bond. That strong bond means it takes a long time for them to break down in the environment.

Because they don't degrade easily,PFAS are used in everything from paper packaging for food, to dental floss, glass cleaner, carpeting, guitar strings and a wide variety of other products.

The vast majority of these chemicals have not been tested for toxicity.- Miriam Diamond, University of Toronto

Researchers are just beginning to understand some of the negative health effects linked to exposure to PFAS.

Miriam Diamond is a professor with the University of Toronto's School of the Environment who studies PFAS.

"The vast majority of these chemicals have not been tested for toxicity," she said. "For the few that have, there are definite concerns about toxicity."

They include links to liver and prostate cancer, pregnancy-induced hypertension, fatty liver disease and affecting lipid function, which is linked to Type 2 diabetes.

Since 2013, Ontario's Ministry of the Environment, Conservation and Parkshas been measuring levels of 11 different PFAS chemicals in Trout Lake, where thousands of people in North Bay get their drinking water.

Last year, the average measurement of those 11 substances was 56 nanograms per litre. One nanogram is one billionth of a gram.

The Ministry of the Environment's interim advice value, or recommendation, for PFAS in drinking water is 70 nanograms per litre. Those values are based on a guideline from Health Canada.

But Diamond saidthe PFAS levels in Trout Lake still concern her.

"They may be lower than the Health Canada guideline, but the Health Canada guideline doesn't reflect the latest evidence," she said.

Health Canada is currently working with the provinces, territories and other federal departments to propose a new objective of 30 nanograms per litre for the total sum of all PFAS measured in drinking water.

If that passes, North Bay's levels would be nearly double Health Canada's recommendations.

The U.S. Environmental Protection Agency (EPA) is proposing an even stricter guideline of four nanograms per litre for one particular type of PFAS called per fluorooctane sulfonic acid (PFOS).

PFOS levels in Trout Lake last year averaged 29 nanograms per litre, or seven times the limit being proposed by the EPA.

The Ministry of the Environment has measured much higher concentrations of PFAS in parts of Lees Creek, which runs from the North Bay airport to Trout Lake. The ministry has measured up to 772,160 nanograms of PFAS per litre in some naturally occurring foams in the creek.

The creek has had a fishing ban for several years because of those high concentrations.

DND's own testing near the airport, which started in 2017, found two wells had PFAS concentration levels above Health Canada's recommendations. Those wells supplied water for five homes.

As of October, DND has tested PFAS levels at 163 properties near the airport. Twenty-two of those properties have received an alternative water supply due to high concentrations.

Remediation plans

The new remediation plans are expected to address contamination at the former firefighter training site at the airport.

DND and the City of North Bay have hired engineering firm Jacobs to lead the $20-million project.

"What we'll be doing this coming year at the firefighter training area is excavating some soil and actually sending it off site to a facility in Ontario that does soil recycling," said Carol Mowder, a chemical engineer and Jacobs's senior technical consultant for the work in North Bay.

"They'll be cleaning the soil up and removing the PFAS."

Mowder said they'll also explore ways to filter contaminated groundwater at the site.

"So one option that we are considering would be to put in activated carbon into the ground," said her colleague, Travis Tan, Jacobs's project manager for the North Bay remediation.

"It's kind of like a Brita filter that will filter the PFAS before the groundwater leaves the site."

But a North Bay environmentalist is concerned the remediation won't address PFASthat already enteredlocal waterways over several decades.

"I did not get the read from the city's announcement of limited remediation options for the airport properties that those other areas of contamination were going to be addressed," said Brennain Lloyd, the project co-ordinator with Northwatch, an environmental advocacy group based in North Bay.

Karin Pratte, the city's lead on the remediation project, said there could be future phases to the project to address downstream contamination.

"The results of the impact of this first phase on downstream will be determined through ongoing monitoring," Pratte said.

"And depending on the results of this first phase and the success of the first phase, then yes, there may be future phases."

But future phases would require more funding, she added.

DND will cover 97 per cent of the cost for the current remediation plans.