Saint-Laurent River | A decontamination operation to remove nearly a thousand tires

Webbed feet of an unusual type are invading the Saint-Laurent this weekend.

Led by underwater explorer and filmmaker Nathalie Lasselin, volunteer divers are surveying the bottom of the river near Beauharnois, in Montérégie, to remove hundreds and hundreds of tires that have been polluting the aquatic environment for several decades.

These tires come from a breakwater made up of 40,000 of them, which was installed in 1990 to expand the Beauharnois marina and which has since sunk. However, the tires were attached to each other by rubber straps containing urethane, a chemical substance that, at too high a concentration, can cause health damage. Added to this, of course, is the microplastic pollution caused by the tires themselves and by the plastic that surrounded them when they were put in the water.

This is a new type of mission for M^me Lasselin, a member of the non-profit organization Aqua Sub Terra, whose mission is to protect and promote aquatic and underground resources. The diver has already dipped her fins in the river several times, both around Montreal and in other areas, and has been organizing clean-up operations in the river since 2017. She has seen everything from classic cell phones and car wrecks to drones and firearms.

She heard about these tires a few years ago, just after crossing the river from Île Perrot to Repentigny. “A pretty sad story,” she says. When the first ice came out, the tire breakwater “didn’t hold up,” the man told her. “The tires ended up a little bit on the bank, but mostly at the bottom of the river,” she says. “So there have been thousands of tires at the bottom of the river for 35 years.” That’s why she decided to tackle this problem last year.

One problem always leads to another, and the question of an environmentally friendly method quickly arose to organize this clean-up dive. And after inquiring with government authorities, the only solution that emerged was to remove the tires by hand and one by one.

About twenty hand-picked volunteer divers make up Nathalie Lasselin’s troops for this mission. Divers who are necessarily experienced, because they must advance solo with “zero visibility” and the risk of hitting objects or getting caught in fishing lines, explains the M^me Lasselin: They will have to cut the rubber straps that hold the tires with a knife, attach them to a buoy so that the tires can then be taken out of the water from a boat.

Minimum target of 1000 recovered tires

During these 15 days, she hopes to remove between 1,000 and 1,500 tires from the river. A small number compared to the quantity of tires remaining under water, out of the original 40,000. Their number is unknown, because some had been recovered as early as 1990 and others had washed up on the shore and still others had been removed because they were an obstacle to navigation, but no estimate of the number remaining has been made.

The action could be repeated from year to year. However, the explorer warns that not all of them can be taken out of the water, at the risk of doing more harm than good.

In fact, the tires located under the layer of sediment that lines the bottom of the St. Lawrence will have to stay where they are, because stirring up the sediment also risks stirring up layers of contaminants that have been present for a very long time, explains Nathalie Lasselin.

The motivation of the volunteers is not affected by this, however, because it is, to use Nathalie Lasselin’s words, a “committed dive”. “I think it is [le fait] to do a dive with an objective, with a goal, with a mission and to say to yourself “well there you go! I’m lucky to be a diver and I can make myself useful at the same time, I’m doing something concrete for the environment.”

The tires removed from the water must then be revalued in a virtuous circle, although the method may leave one perplexed as to the virtue of the thing. They will be incinerated. But not in just any context. “The tires will be managed by an accredited member of Recyc-Québec, which is Géocycle, in their Saint-Constant plant,” reassures the diver.

Their incineration at a very high temperature, with strict standards to limit pollutant emissions, will be used to produce energy to manufacture cement. “We are not in a perfect world,” recalls M^me Lasselin, but the incineration of these tires will avoid the use of another fuel such as coal, because hydroelectricity is not sufficient to provide the enormous amount of energy needed to produce cement.

The other objective of the operation is of course to raise awareness among the population about the pollution of the environment by our waste. “We can no longer walk anywhere in the boreal forest or elsewhere without seeing traces of human presence, whether it be aluminum cans, plastics, waste, coffee packaging, etc.”, protests the organizer of the mission. “We are going to take action to finally tell the world, ‘you know what? We can change things.'”

The Saint Lawrence, recalls Nathalie Lasselin, despite its green-brown waters clearly less inviting than a postcard lagoon, is a very rich environment where many animal and plant species live side by side, while the harmful effects of our waste are still unknown, but are changing the aquatic environment.

The committed explorer is waiting for the end of the operation to assess the team’s ability to remove tires and what more can be done. But she plans to organize a new mission of this magnitude next year.