Phase II Environmental Site Assessment of a Set of Lots in Preparation for Road Infrastructure Redevelopment
Terrapex was mandated to conduct Phase I and II Environmental Site Assessments in the context of a maintenance and improvement project for an interchange integrating public transit measures.
The Phase I ESAs retraced site activity to the beginning of the 20th century. Commercial and industrial buildings as well as rail lines occupied the site until the beginning of the 2000s, at which point the sector fell vacant. Document consultation made it possible to confirm the presence of storage tanks, rail lines, designated activities and storage on the subject sites and neighbouring properties. In view of the Areas of Environmental Concern (AECs) identified on the three sites and the risk of soil and groundwater contamination, Phase II ESAs were recommended to verify soil and groundwater quality.
During the Phase II ESA fieldwork, different characterization methods were selected to meet the various objectives. Test pits were cut in areas suspected of containing residual materials to provide a clearer view of the materials in place. In fact, asbestos fibres were observed by the technical team during sampling. This observation made it possible to adjust OHS measures to ensure personnel protection. Boreholes were drilled for the installation of monitoring wells as well as in locations where backfill at depth was a potential concern.
A total of 77 test pits and 35 boreholes, 22 of which were converted to monitoring wells, were undertaken. The chemical analyses allowed for the delineation of contaminated soil and residual material enclaves as well as enclaves containing asbestos. Granulometry, accompanied by chemical analyses in connection with the RVMR (Règlement concernant la valorisation de matières résiduelles; “Regulation Respecting the Reclamation of Residual Materials”) as well as leachate tests to characterize residual materials as defined in the RMD (Règlement sur les matières dangereuses; “Regulation Respecting Hazardous Materials”) were performed. When the data was obtained, recommendations were made in the report to guide the client in future work phases and in managing each enclave according to current standards.
A hydrogeological study was also conducted, in parallel to the Phase II ESA work, to estimate flow rate adapted to the different design scenarios envisioned by the client for the road infrastructure redevelopment project. The installation of a settling basin to collect rain sewer discharge was considered on one of the (Phase II) assessed sites. A complementary hydrogeological study was therefore carried out onsite by Terrapex to determine certain parameters to consider in the project design. Hydraulic conductivity testing was undertaken on the different stratigraphic units encountered. Groundwater supply from the water table to the basin was then estimated in view of site geology and the set of hydraulic parameters defined in the study. A first estimate was supplied based on the development plan initially provided by the client. The development plan was still in the design phase at the time of the study; flow rate was also estimated by modifying the initial development plan.
