St. Lawrence raw sewage dump on hold after public outcry

The City of Montreal is putting the brakesonits planto release untreated wastewater directly into the St. Lawrence River next month.

The city says it has to do important work on a major sewer interceptor, startingOct.18and lasting about one week.

Why have we put in place water-filtration plants if the water can dilute everything?- Water-treatment specialistAbdelazizGherrou

Earlier this week, the city said it had no other option but to divert about eight billion litres of untreated wastewater from the sewers into the St. Lawrence.

The province's Environment Ministry hasapproved the decision.

However, the city is now reconsidering the plan after news of the sewage release became public this week.

Pierre Desrochers, the chairman of Montreal's executive committee, said Mayor Denis Coderre hasasked that thework be stopped and re-evaluated before proceeding.

Projet Montral city councillor Craig Sauv said he was pleased to hear the work has been put on hold, addinghe wondered whether there weren't better solutions fordisposing of human waste in this day and age.

"It's 2015. We should have a contingency plan, not fire out eightbillion litres of untreated wastewater into the river," Sauv told CBC. ""I'm not a water expert, but it seems that there are other things we could do."

The city said it wouldn't give any further interviews on the subject until after a decision has been made about how it will proceed.

Harming the river ecosystem

It's been six years since the last time the city dumped raw sewage into the river.

Dr. Grant Brown, aConcordiaUniversity biologistspecializingin aquatic behavioural andchemical ecology, said the untreated effluentcould cause harm toa number of aquatic species.

Brown said fish rely on chemical cues to help themperform tasks such as finding food, findingshelterand detecting and avoiding predators tasks that are necessary for survival.

The wastewater going into the river could throw them off.

''You're depriving an entire ecological community of a source of information. It would be akin to [us deciding]to put a dome over the city and completely paint it black, so nobody could see," Brownsaid.

Carrying waste down the river

QuebecEnvironment Minister DavidHeurtelandChantalRouleau, the city's executive committee member responsible for water, contendthe temporary measure would have minimal consequences forthe environment.

City spokesman PhilippeSabourinsaid contamination is not a big concern because of the sheer size of the river and how quickly it flows at a rate of 6,000 toto 7,000 cubic metres a second, compared to the flow rate of the wastewater,expected to be just 13 cubic metres a second.

However, civil engineerIsabelleJallifier-Vernesaid any human waste carriedby the current could have negative consequences for communities downstream from Montreal.

She said the effluentcould also pollutethe riverbanks, potentially posing a threat to the plant and animal life that live along the water's edge.

Water-treatment specialistAbdelazizGherrousaid there's no telling how extensivethe environmental toll ofuntreatedwastewater would be.

"Why have we put in place water-filtration plants if the water can dilute everything?"Gherrouasked.