Cathy Dobson
Should Sarnia invest in a pricey remediation to clean up oily contaminants moving underground in Canatara Park?
Or will a relatively inexpensive fix do?
City staff remain optimistic an ongoing study will conclude that mitigation measures costing about $130,000 will stop seepage from an old landfill moving toward Lake Chipican.
But at least one city councillor wonders if a complete cleanup will be needed.
“Do we really know what we have underground?” Coun. Margaret Bird asked during a recent council discussion.
“These studies have been going on for years. If there’s even the slightest risk of an explosion in a recreational area then maybe further containment is not the way to go.”
The 69-acre landfill beneath the park’s south side accepted municipal and industrial waste from 1929 to 1967.
After it closed, the dump was capped with a metre of soil, but later began leaking oil and diesel fuel that threatened to pollute Lake Chipican, a central feature of the busy park.
The city responded by installing an underground steel wall as a barrier. Permanent monitoring wells were added to collect and pump out the industrial waste. Additions to the steel wall were necessary over the years, with the last one installed in 2014.
For years, the wells collected as much as 1,000 litres of oil a month. But last year something changed and the volume increased to as much as 5,000 litres a month, said city engineer David Jackson.
He has suggested higher Great Lakes water levels are a factor.
Guelph-based RWDI Air Inc. was hired to drill a series of 191 boreholes, many of them near the lake, to analyze the situation. Laser induced fluorescence technology is also being used to determine if contaminants are drifting farther than expected.
The good news? The city concluded no landfill vapour is seeping into nearby residential areas, and Point Edward officials confirm there have been no complaints suggesting otherwise.
However, RWDI Air has found light non-aqueous phase liquid, or floating oil, in three distinct areas: near Lake Chipican area, along Michigan Avenue, and near Point Edward’s residential neighbourhoods.
But the consultants’ final conclusions won’t be known until at least the New Year.
Meanwhile, the city has authorized another $45,000 for the study, bringing the total to $145,000.
Jackson told council earlier this month he’s hopeful another extension of the underground wall and more permanent monitoring wells will contain the problem.
For that, he asked council to set aside $130,000 in the 2021 budget.
An attempt to completely remediate the park could cost $30 million to $40 million, Jackson said, adding it’s standard practice for municipalities to use mitigation and recovery methods to contain old landfills.
Sarnians are well aware of the painful cost of major remediation after Centennial Park was closed for almost five years to complete $13.5-million cleanup.
Centennial’s history surfaced in 2012 when a sticky tar rose to the surface in a high traffic area. Soil tests revealed asbestos and other contaminants in the soil.
A large berm was created on the park’s west side where contaminated soil was buried and capped.
Had the contaminated soil been removed from Centennial Park, it would have cost $30 million to $40 million, officials estimated.
