A review by Environment Canada, is the latest development in the controversy surrounding the City of Montreal’s plan to dump eight billion litres of untreated sewage into the St. Lawrence River.

Montreal Mayor Denis Coderre has stuck by the plan, saying it is needed for the lowering of the Bonaventure Expressway. A large snow dump that is connected to the sewer interceptor needs to be moved for the construction project and maintenance is required on the interceptor itself. To do these things, the interceptor needs to be drained.

The lack of alternatives and debate over the issue led two groups of scientific experts to go public with “limited support” for the City’s plan said the CBC.

Sarah Dorner, associate professor of civil, geological and mining engineering and the Canada Research Chair in source water protection, told CBC Montreal’s Daybreak that the City has no choice but to divert the wastewater into the river.

“There really is no other engineering or technical solution to this,” Dorner said to CBC.

Opposition to the plan has come from many sides, including environmental activist Erin Brockovich and U.S. Senator Charles Schumer. An online petition at Change.org has gained over 90,000 signatures and will be presented to Mayor Coderre at a council meeting, according to the CBC.

Last week, Minister of the Environment Leona Aglukkaq gave the following statement in a press release:

“The St. Lawrence River is one of Canada’s most important waterways, acting as a home to several species of whales and fish, while providing millions of Canadians with their drinking water. What’s more, it’s also enjoyed by many Quebecers for recreational purposes.”

“The proposed plans by the City of Montreal to dump billions of litres of untreated raw sewage into this important river are very concerning – as many citizens have noted publicly.

Section 36 (3) of the Fisheries Act prohibits “the deposit of deleterious substance of any type in water frequented by fish.

Upon my request, Environment Canada has contacted the City of Montreal to gather further information on their plans and to assess the potential environmental implications.

I have requested Environment Canada to explore options to prevent this release while we gather more information on the environmental impacts of the City of Montreal’s plans. I ask that Mayor Coderre halt his plans while a proper assessment is done.

We will continue to monitor and assess this situation closely to ensure the protection of Canadians and their environment.”

However, news media have reported that the federal environment minister had known about the raw sewage dump since 2014. According to Global News, documents obtained by The Canadian Press show the federal environment ministry was copied on correspondence relating to the project, including the expected work start date of October 2015.