The race is on to remove the oil from nearby waterways before the spring thaw, after a crude oil spill near Gogama, Ont. last month.
It's estimated that over one million litres of bitumen was released after a CN train derailed last month.
CN says the crude oil has reached a nearby pond and a localized area of a lake — but it's being detected at very low levels.
And a spokesperson for the Ministry of Environment and Climate Change, Kate Jordan, said those levels are decreasing each day.
“CN is doing daily surface water monitoring in waterways near the derailment site. Sample results have indicated levels of petroleum in the nearby creek, pond and Kasasway Lake,” she said.
“These levels are decreasing over time and are non-detectable further downstream in the lake. Ministry staff continue to monitor clean up efforts and are currently on site."
Jordan added the ministry has “now received CN's proposed plan for discharging the treated water from the site. We are currently reviewing it and will be meeting with the company to discuss further. "
The ministry is waiting for a detailed report from CN that could help understand how much crude oil entered the waterways.
A ‘better situation’
The director of CN public and government affairs said dams created in the area “successfully prevented any bulk crude oil from migrating beyond the stream.”
“Following the Feb. 14 derailment near Gogama, CN environmental teams dammed an unnamed stream that flows through the derailment site,” Jim Feeny said.
While monitoring and remediation programs continue, “CN hosts daily conference calls with all regulatory bodies, to discuss the ongoing programs and to provide updates site information and data."
The director of Vale's Living with Lakes Centre at Laurentian University said the time of year is an ally at this point.
"Of bad things that can happen, this is one of the better situations where you're not contaminating a very large system and it's readily observable,” John Gunn said.
"Winter conditions are a pretty slow-moving time of year. So we're not seeing the spill happen in a spring flood period or a very large system, so I would suspect the movement of this particular oil spill in Gogama is very slow and very localized."
The Sudbury and District Health Unit said the oil spill near Gogama doesn't pose a threat to drinking water.
But it's monitoring the situation.
Burgess Hawkins, manager of environmental health at the health unit, said people nearby will be notified if their drinking water becomes affected.
“We would be attempting to contact those people. The exact way we would be doing so right now would be up in the air because we'd have to try to figure out where they are located because obviously if they're at a cottage there, they're not there full time,” he said.