The client used this island along the St. Lawrence River for the manufacture of mineral acids and alum since the early 1940s. As a result, considerable volumes of industrial wastes existed on the island. In addition, the sediments found in the zone adjacent to the island were also impacted by industrial activities.
AECOM performed an exhaustive characterization on the sediment zones surrounding the island, including an ecotoxicology study. Several scenarios for remediating the contaminated sediments were evaluated. Subsequently, notification for the preferred solution (covering the sediments in the priority I zone) was submitted to the Ministère de l’Environnement et de la Faune. AECOM is currently preparing the environmental impact study for this remediation project. The remediation method retained consists of capping the contaminated sediments in the priority I zone (approximately 70,000 m2) with a geotextile and granular material (sand and gravel). A rip-rap was installed to protect the structure from waves and ice action.