Une fuite d'oléoduc trouve vite son ruisseau

Photo: insideHalton.com

On a aperçu de l'essence dans le ruisseau Bronte Creek le 11 mars: cela venait d'une fuite dans un pipeline appartenant à Trans-Northern Pipelines Inc, sur un terrain appartenant à Suncor.

Le nettoyage du déversement s'est fait par la ville au début, puis Suncor a pris la relève. Le produit pétrolier semblait sortir de la rive est de Bronte Creek dans une section appartenant à Suncor, vis-à-vis la raffinerie de Petro Canada. Trans-Northern Pipelines a avisé le ministère de l'environnement de l'Ontario le 16 mars qu'un de ses oléoducs contenant de l'essence avait une fuite. Ce pipeline est enterré à 350 mètres au nord de l'endroit où l'on a aperçu l'essence dans le ruisseau, 2 mètres sous terre. Le pipeline a été réparé et à priori, on estimait que 100 litres d'essence avaient été déversés. Le ministère de l'environnement exige que Trans-Northern nettoie le site et délimite l'étendue du déversement qui semble plus considérable que l'on pensait alors.

Le gérant de Trans-Northern pense que bien que la fuite a été découverte le 16 mars, elle avait probablement commencée le 11, la journée que l'essence a été aperçue dans Bronte Creek. La vitesse de propagation surprend le gérant, car cela voudrait dire que l'essence a parcouru 300 mètres en très peu de temps. Grâce à un radar qui sonde les sols, il a découvert un ancien fond de rivière que l'essence a probablement emprunté pour s'étendre si rapidement.

D'où le besoin de limiter la dispersion de la contamination et les précautions à prendre pour décontaminer le site. Le ruisseau est un cours d'eau d'une telle importance que l'on ne peut pas simplement tout creuser et retirer tout les sols contaminés. On étudie encore d'autres façons de nettoyer les lieux, soit par bio-rémédiation ou par produit chimique qui oxidiserait l'essence.Photo de Bronte Creek de flyfishOntario.ca

"Gas spill in Bronte Creek

The ministry of environment says it will use regulatory powers if it has to to get a gasoline spill in Bronte Creek cleaned up quickly. A ministry spokesperson says the 300-metre long spill in the creek is being watched closely.

Gasoline began seeping March 11 from a pipeline owned by Trans-Northern Pipelines Inc. on property owned by Suncor. Trans-Northern has placed containment booms in the creek in the area north of Speers and Bronte roads and underneath the Rebecca Street bridge to absorb any additional gasoline seeping into the creek.

The discovery sparked an environmental clean-up effort on the part of the town, which was eventually turned over to Suncor. The petroleum product appeared to be oozing out of the east bank of the portion of Bronte Creek that flows through the Suncor property site, opposite the Petro Canada Refinery.

Trans-Northern Pipelines Inc. notified the Ministry of the Environment March 16 of a leak in one of its gasoline pipelines, which is buried only 350 metres north of where the Bronte Creek slick was seen. The pipe, which carries a variety of petroleum products to the Suncor facility and is located two metres underground, was fixed and returned to service. It was previously estimated 100 litres of gasoline were lost as a result of the leak. The Ministry of the Environment is requiring Trans-Northern to clean up the site and outline the extent of the contamination, which now appears greater than originally believed.

Gary Robinson, Trans-Northern manager, said while the leak was found on March 16, it had probably been leaking since around March 11, the day the slick appeared in Bronte Creek.This is perplexing for Robinson because it means the gasoline moved more than 300 metres in just a few days, if not hours. "On clay soils it would take weeks or months for that to travel just a couple of dozen feet, " he said. Through the use of a ground penetrating radar, Robinson believes he has found an answer to this riddle in the form of an ancient river bed, which may have served as a pathway for the gasoline and allowed it to move so quickly.

With the extent of the contamination now known, the task becomes keeping it from spreading and cleaning it up. "This site is not conducive to digging and dumping (the contaminated soil). You can't just go down there and make it into an open pit mine, Bronte Creek is too valuable a resource to treat it that way, " said Robinson."We are looking at bio-remediation, which means we can inoculate the subsurface and the ground water with a nutrient material that actually consumes hydrocarbon, but we have to be very careful that these things don't start eating other things that are down there naturally. So that's still being assessed."

A chemical material that dissolves gasoline is also being considered by Environment Canada and the Ministry of the Environment, as an option to oxidize the fuel."

Excerpts from article signed Metroland Media published here: http://www.thespec.com/News/Local/article/763451