The talk over Montreal’s big sewage dump just isn't going away. The plan is to dump eight billion litres of raw sewage into the St. Lawrence River, and while some are arguing that's just a drop in a bucket, others say the plan must be stopped.

Quebec’s Environment Minister David Heurtel was grilled again in the National Assembly about the plan that his department approved.

He says studies provided by the city of Montreal reveal the environmental impact will be minimal, but no one is sure what to believe, including people living downstream.

“They just don't really know what the impact will be,” said one man, adding they need to find another solution.

A report prepared by the environment ministry concludes Montreal’s solution “is not ideal but it is the best in the circumstances, in particular to avoid impacting the operation of Montreal’s wastewater treatment plants.”

But that's not so simple. Sarah Dorner, a professor of environmental engineering at the Ecole Polytechnique, says she and her graduate level class looked for alternatives.

“Lots of ideas, a very lively discussion. No one came up with anything because what it comes down to is it's a limited duration spill and the cost would be completely unreasonable,” she said.

Earlier this year, Longueuil emptied 150 million litres of raw sewage into the St. Lawrence. In 2013, across Quebec there were 45,000 other sewage spills into lakes and rivers throughout the province. Montreal dumped raw sewage into the St. Lawrence up until 1980.

“Why deal with this specific instance when this is a wide spread problem throughout the province?” Dorner said.

And even though we're talking about 8 billion litres of sewage, Dorner said she believes the timing is right because fewer people are swimming in the river, and she doesn't think it will affect anyone's drinking water.

But scientist Daniel Cyr is worried. He says his research team is already finding effects on fish swimming in basins with treated sewage, so he believes this much untreated sewage all at once will be harmful.

“It's wrong to think it's just the fish. We’ve gone out and done sampling in the summer, and there are people who run in and run out of the water, even though it says no swimming, there are people eating the fish,” he said.

Environmentalists say if there's one positive coming out of this debate, it's that Quebecers are finally speaking about the health of the river and that could lead to changes about how we protect the St. Lawrence.

One big change will happen in 2018, when the city's sewage will be treated by ozonation.