London's airport is among Canada's hotspots for 'forever chemicals'

The property where London's airport is located is among scores of locations in Canada being monitored for the presence of so-called "forever chemicals," which can pose a threat to human health through groundwater contamination.

CBC News recently published a feature story mapping the locations in Canada known to be contaminated with the chemicals called perfluoroalkyl and polyfluoroalkyl substances, or PFAS for short. The chemicals have been used for decades in a variety of products, including fire-retardant foam. A section of what is now London's airport was a former training ground for firefighters.

The airport is operated by London's airport authority, which rents the property from Transport Canada.

Transport Canada confirmed to CBC News that a risk management plan for the airport was completed in 2015. The 40-acre site is also subject to long-term monitoring of 28 wells on the property.

In a statement to CBC News, Transport Canada said the risk management plan for the airport site includes "provisions to monitor for contaminant migration and potential impacts to drinking water."

The statement also said Transport Canada has "communicated with property owners beside the airport and collected information regarding well usage in the area."

Transport Canada suggested CBC News submit a request under the Access to Information Act to obtain reports about the site and the data generated by the monitoring.

CBC News spoke with a handful of property owners who live near the airport. None said they were aware of the presence of PFAS chemicals on the airport property. They also said they've not received any information about the presence of PFAS chemicals from Transport Canada.

Claire Robinson is a professor of civil and environmental engineering at Western University. She's also the Canada research chair in water quality.

Robinson said PFAS chemicals are considered carcinogens and pose the biggest threat to human health if they get into groundwater.

She said PFAS chemicals are also notoriously difficult and expensive to remove from a contaminated site.

"One of the real challenges with these forever chemicals is because of their chemical structure," said Robinson. "They're very challenging to break down or clean up."

Most London residents inside city limits are supplied with treated municipal water from Lake Huron and Lake Erie. However, many of the properties around the airport rely on wells.

The airport is also located close to Fanshawe Lake, which feeds into the Thames River.

Robinson said PFAS contamination at airports is not uncommon.

She said that because removing PFAS chemicals can be so expensive, landowners often monitor the sites for years "to understand what's there" and to see if removing the chemicals is worth the cost.

The Upper Thames River Conservation Authority said they rely on other organizations to monitor for the presence of PFAS chemicals in groundwater.

"This is the first we've heard of a site being contaminated with PFAS in our area, and no data has been shared with us to date," they said in a statement to CBC News.

"Testing is extremely expensive and time-consuming to undertake; therefore, we rely on researchers in the field to assess the risk and determine if there is a need for further action."

Based on information Transport Canada has posted on its website about the London airport site, more than $1.8 million has been spent on remediation of the site stretching back to 2006. The online listing describes London's airport site as a "high priority for action."