Mayor Denis Coderre is shrugging off federal concerns about the city's plan to to dump eight billion litres of raw sewage into the St. Lawrence River, saying he's confident that it's the best option.

Earlier Monday federal Infrastructure Minister Denis Lebel joined the chorus of doubters about Montreal's plan. 

"We are very concerned with the situation around Montreal's decision to dump wastewater in the St. Lawrence River," Lebel said in a statement.

"Yeah, like this government on the environment is important," fired back Coderre at a news conference hours later.

Coderre questioned Lebel wading into the debate.

denis coderre

Montreal mayor Denis Coderre said the plan to dump 8 billion litres of sewage into the St. Lawrence will go ahead as planned.

"Are you telling me Mr. Lebel want to play politics with this file," Coderred asked reporters. 

Environment Canada says it is still conducting research and assessing the "potential implications" of the City of Montreal's plan to dump wasterwater into the river.

The city is expecting the ruling in the coming days.

"At the end of the day I think it's at the administration level, it factual, and we've done this before," Coderre said, referring to 2003 and 2007, when Montreal was allowed to make similar sewage dumps.

St. Lawrence River

The City of Montreal announced last Friday it will go ahead with its plan to dump untreated wastewater into the St.Lawrence River. (Thomas Daigle/CBC)

"I want to reiterate that the option we chose today, we had no other choice. We looked at all angles."

The new dump is necessary as the city rebuilds the riverside Bonaventure Expressway.

As a result, the city plans to temporarily divert a sewer interceptor, which would see eight billion litres of wastewater dumped into the river for a week starting Oct. 18.

Environment Canada still assessing plan

In a statement on Sunday, Environment Canada spokeswoman Barbara Harvey said Environment Canada is in communication with the City of Montreal, "gathering information and assessing the potential implications,"

The city has Quebec's approval for the temporary measure to divert a week's worth of sewage from one of the city's main interceptors into the St. Lawrence. The diversion was supposed to begin Oct. 18, but it's not clear whether it will proceed according to schedule.

"I can tell you that ‎under the Wastewater Systems Effluent Regulations, Environment Canada cannot authorize this type of wastewater deposit. The Fisheries Act prohibits unauthorized deposits of deleterious substances into water frequented by fish," she said.

The plan has sparked criticism far and wide, including south of the border.

New York senator Patty Ritchie sent a letter to the International Joint Commission — the group tasked with protecting the St. Lawrence River and the Great Lakes — to look into the plan. 

"While I realize that the dumping will occur in Canadian waters, downstream from any U.S. communities, I am very concerned by the precedent Montreal is setting for other communities along the St. Lawrence and the lakes," she wrote.

City waiting on approval

The city acknowledged over the weekend that it is indeed waiting for Environment Canada's decision to know whether it can proceed with the plan.

"Yes, it takes an authorization, that's why we asked for it," said city spokeswoman Valérie De Gagné.

Sylvain Ouellet from the city's opposition party Projet Montréal said Environment Canada hasn't authorized the dump — but it hasn't not authorized the dump either.

"It leaves it open to interpretation. Is it a definite no? Or is it a 'No, we haven't got the final analysis'?" Ouellet asked.

Petition seeks alternatives

Over the weekend, Xavier Nonnenmacher created a petition called "The St. Lawrence is not a garbage" to try to stop the dump. It has since collected more than 50,000 signatures. 

He told CBC Daybreak on Monday that he plans to give the petition to the mayor as soon as possible.

"It's [the biggest river] in Quebec, and many people live with this river, drink the water every day. This is why people are concerned," he said.

The petition is addressed to Sorel-Tracy, Que., Mayor Serge Péloquin, as well as Montreal Mayor Denis Coderre and city hall opposition leader Luc Ferrandez.