Work is underway to stop the spread of oil plumes migrating underground in certain areas of Sarnia’s Canatara Park.
Contaminants from the former Michigan Avenue landfill have long been seeping beneath the popular park, but recent monitoring showed floating oil is spreading toward both a residential area in nearby Point Edward and Lake Chipican.
“With all the higher groundwater levels we were experiencing when the river levels rose there for a couple years — it caused some of the oil on the site to migrate,” said Joe Boothe, the city’s manager of environmental services. “And product started moving into areas we’d never seen before.”
The 69-acre landfill, which lies 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 have been 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 in 2019, the volume increased to as much as 5,000 litres a month.
Using Laser induced fluorescence technology, officials were able to determine that the oily waste, or non-aqueous phase liquid, was spreading towards the west end of the property near Ernest Street in Point Edward, as well as near Lake Chipican.
Last fall, council approved an emergency plan to install additional barriers and monitoring wells, but shipping delays stalled the project until this month.
Work began last week to install vertical steel strips into the soil, forming a “wall” at the west end of the park.
Similar work at Lake Chipican will follow, “to ensure that it doesn’t travel any further,” Boothe said, noting the project is expected to take two weeks.